A Hyperlink Junkie's Illustrated Field Guide
to the 1969 Triumph Bonneville
Most recent online update: 15 January 2021
World Wide Web
Tip Caution Danger
Links for parts and service providers, accessories, books, clubs, history, tools, technical info, and more.
ResourcesBaconsdozen Kevin C. Bacon's history and descriptions of Whitworth (BSW), BSF, BSC, UNC, UNF, SAE, AF, and BA. Includes Bacon's own size charts with conversions to metric and decimal inch dimensions. A must-read, top to bottom, richly informative.
Note that while American wrenches are measured across the flats (AF) of the bolt head, wrenches for the bolts in the British standard thread family are measured by the diameter of the bolt's threads.
ResourcesTriumphRat.net John Healy: Where to use Loctite on a Triumph
Speaking of the 'Right Stuff', I think I finally figured out how to get the stuff off! Gasoline and friction.
And speaking of sealing stuff up, should I be using a sealant on the splines for the engine and gearbox sprockets? Too late this year (2018).
ResourcesBritBike.com "Heating Engine Cases & Other Parts"
For removal of tight or seized parts, heat is a big help. But for amateurs like myself, The big question is, how MUCH heat? And how to apply it?
ResourcesWorkshop Manual (1969 650cc Twins) Section A: Lubrication Table of Contents
ResourcesWorkshop Manual (1969 650cc Twins) Section A3: Engine Lubrication
According to the article "Tech 101: Zinc in oil and its effects on older engines", modern oil manufacturers have reduced the amount of 'zinc' (actually ZDDP [zinc dialkyldithiophosphate] or ZDTP [zinc di- thiophosphate]) in their products for various reasons, including prolongation of the life of catalytic converters. When used in older (classic) car and motorcycle engines, the low-zinc products fail to provide sufficient protection against start-up engine wear.
I used a list showing the percentage of zinc content for popular oils to help select an oil with a higher zinc level
for Bonnie. I've been using Shell Rotella 15W-40 since around 2014.
ResourcesWorkshop Manual (1969 650cc Twins) Section A4: Changing the Engine Oil & Cleaning the Filters
The Triumph manual specifies an oil change interval of 1,500 miles. There was no oil filter in the day.
I equipped Bonnie with an oil filter and I change engine oil and oil filter at 1,000 mile intervals. At the same time I change the engine oil, I change the primary chaincase oil, which the manual states should be done at 1,000 mile intervals.
Note that some Triumph owners/mechanics would council us against removing the crankcase drain bolt because of the risk of contamination. They make the point that it's nearly impossible to clean the area around the drain plug due to its proximity to the case joints and the angle at which the two intersect.
For a long time I cleaned thoroughly around the plug and drained the crankcase with every oil change. Since very little oil drains from Bonnie's crankcase, usually less than a quarter of a cup, I have since joined the camp of cleaning the crankcase drain and oil tank drain once a year. That and other stuff to do after the snow flies.
At 43,000 miles, I fit Bonnie with a Norton oil filter head, connected as diagrammed below. The mounting bracket was fabricated based on Glenn "Phrog" Davidson's design.
Note that the oil tank connections and the oil pipe junction block pipes are 1/4", while those of the Norton filter head are 3/8".
In 2018 I used 5/16" Gates Automatic Transmission Cooler Hose for the hoses connecting to the filter head. The 5/16" is a very tight fit on the 3/8" fittings, and somewhat loose on the 1/4" ones. Ok once clamped - no leaks after several thousand miles.
Filters I used with the Norton filter head satisfactorily include:
In 2017 I picked up a simple thread-in oil filter adaptor from Colorado Norton Works. The adaptor facilitates using filters which are more available and potentially less expensive.
ResourcesWorkshop Manual (1969 650cc Twins) Section A21: Check Procedure for Wet Sumping
ResourcesWorkshop Manual (1969 650cc Twins) Section A12: Primary Chaincase Lubrication
The primary chaincase lubrication information presented here pertains only to unit 650 twins manufactured before late 1969. The crankcase oil and primary chaincase oil of unit engines before 1969 were kept completely separate, while later engines 'shared' oil between the compartments. Since the modification was introduced in late 1969, it makes its first appearance in Triumph literature in 1970. For data on the later model engines consult the appropriate Workshop Manual.
Change primary chaincase oil at 1,000 mile intervals. Drain and replace with 350cc of 30w non-detergent oil.
The chaincase oil drains slowly because it needs to flow past the primary chain tension adjuster. The drip, drip, drip flow of oil even when it's hot takes hours so I usually give it all day or overnight.
After replacing the drain bolt, pour 350ml of 30w non-detergent oil into the inspection cap on top of the chaincase.
Tighten the drain bolt carefully to avoid stripping threads in the soft aluminum case.
ResourcesWorkshop Manual (1969 650cc Twins) Section A11: Gearbox Lubrication
Opinions differ about using GL5 spec gear oils around the yellow metal bushings and thrust washers used in our Triumph gearboxes.
GL5 oils have high concentrations of sulphur and sulphur reacts with yellow metals chemically to break them down. So say those who believe GL5 is harmful. Yet many others say they've used GL5 for years without problems.
Why take a chance? I was always disinclined to use GL5 gear oil in my Bonnie's gearbox.
Oil companies say GL5 products are now safe because they've reduced active sulphur, which eats yellow metals, in favor of inactive sulphur, which is less harmful while still providing the protective qualities of active sulphur.
I don't find "less harmful" all that reassuring, frankly.
However, since doing my own yellow metal and GL5 experiment I do feel a bit more comfortable about GL5. But I still prefer good old GL4.
For those who harbour doubts, the following list of oil descriptions are those which are said to be, at least potentially, harmful to yellow metals:
For other gear oil recommendations (including many in UK) see this link above in TriumphRat.
There are three hex heads on the bottom of the gearbox: the 3/4" index plunger holder (57-2172); the 7/16BS (3/8W) drain plug with level tube (57-3851); and the 5/16" gearbox level plug (21-0543).
The level plug threads into the drain plug and together they are tucked just inside the frame member on the timing side. Since they are closer to the timing side I always removed and installed them from that side. However, access from that side is awkward due to the proximity of the frame, and recently I realized that it's actually easier to access them from the drive side.
To drain the oil, remove the drain bolt using a 7/16BS (3/8W) socket and a two or three inch extension to clear the frame. Remove carefully to avoid damage to the level tube extending above the drain bolt.
When replenishing the gearbox oil, replace the drain plug after removing the level plug and then add oil, slowly when approaching 500ml, until it overflows from the level plug.
ResourcesBritBike.com " How to stop oil and gear box drain plug leaks?".
ResourcesWorkshop Manual (1969 650cc Twins) Section A16: Front Fork Lubrication
"When changing fork oil remove RHS top nut, remove LHS drain screw, doing opposites stops oil gushing out the top as the bike settles.Read that in the manual, after doing it wrong for years, this saves a lot of mess. I like to flush the old oil with a little kerosene to get the last of the muck out."
ResourcesWorkshop Manual (1969 650cc Twins) Section A10: Contact Breaker Lubrication
ResourcesWorkshop Manual (1969 650cc Twins) Section E2: Removing and Replacing the Oil Tank
From 1967 to 1970 the unit 650 Triumph oil tank was unchanged. However, according to RF Whatley, Triumph made several modifications to engine lubrication in 1966, including a new (and problematic) oil tank design. Whatley says use of the modified design was limited to several months of production and most were changed under warranty. However, an oil tank with the rocker feed coming off the top instead of the bottom is of the problematic 1966 design and should be replaced with a later model.
Use Murphy's Oil soap on the rubber parts.
Important that tank "hangs" well or wear will occur.
One would think that the rubber mounting would incur the wear, but after my first re-assembly there was wear and it was to the tank's mounting peg, not the rubber.
A comfortably loose configuration, adjusted by turning the "C" clamp mounting bracket, should work.
In case you ever need to know, HenryAnthony on Britbike.com forum informs us that the measurement between the barrels holding the rubber upper mounts is 4-1/4", and the measurement between the battery holder straps they bolt up to is 4-1/2".
ResourcesWorkshop Manual (1969 650cc Twins) Section B: Engine (TOC)
ResourcesCycleWorld "What Is The Difference Between Normal And Abnormal Combustion In A Motorcycle Engine?" An overview.
Above video and article (suggested by Truckedup on TriumphRat.org) both explain pre-ignition and detonation and the difference between them. If I've got it right:
Things to beware of:
ResourcesWorkshop Manual (1969 650cc Twins) Section B1: Removing and Replacing the Engine Unit
The workshop manual says before removing the engine to remove the two bottom bolts holding the front and rear frames together on the left-hand side. The first time I removed the engine, I removed the forward bolt's nut, which faces out and sticks out a bit, and pushed the bolt in and out of the way. I left the rear bolt that threads into the frame because it didn't seem to stick out much. After the engine was removed from the left side as per the manual, I couldn't see why removing either one was necessary, unless it's to drain water out of the frame: later when I removed the left, rear bolt, about a quarter of a cup of water came out.
The first two times I removed the engine (complete except for the rocker boxes) I used a rope sling to attach the engine to the chain hoist to assist in pulling the engine out of the frame. It worked better the first time than the second, when I raised the engine too high and got it hung upon the bracket on the frame. The ropes have to run on both sides of the frame otherwise the engine will be tilted while being guided into position. This can be seen in these photos: Removing engine using rope and chain hoist.
In 2018 I removed/installed the engine (twice!) using a floor jack to support the engine while I lifted it out manually, but only after all the transmission and clutch parts had been removed. Makes a good case for assembling the transmission and gearbox in the frame and not on the bench. Removing engine using floor jack & muscle
However the engine is pulled, it's probably better removing/reinstalling the rear/bottom engine mount stud first because the front/top stud has better access for fiddling around. Before inserting the studs through the frame I put a good dab of grease on their ends. Can't hurt.
According to #7 (page 5/ref 38) the bottom bolts on both sides are supposed to have spacers, but they are missing on Bonnie.
Don't be tempted to leave off the head steadies. Apparently they are essential and their absence can result in damage to the frame and/or exhaust ports and exhaust pipes.
I introduced the engine rear end first from the left side. Inserted the front engine mount stud first and then the bottom one. Went up and down a couple of times on the come-along. I drove the stud through from the left-hand side and then used the kickstand as a lever to move the engine to line up the other end.
ResourcesWorkshop Manual (1969 650cc Twins) Section A8: Removing & Replacing the Oil Pipe Junction Block
The oil pipes at the oil junction block (70-6930) are 5/16".
The first time I removed the oil lines from the oil junction block I found the job difficult - partly because the outer and inner gearbox covers weren't removed, but mostly because I lacked technique.
After loosening the clamps and sliding them out of the way, try these:
In desperation the first time I used the plastic mallet to rap against the pliers in order to loosen the flexible line. Not a good technique as the WS manual specifically warns against stressing the metal tubes.
A Few Important Notes
Improperly installed oil lines can result in catastrophic damage to an engine.
The oil pipe junction block connections described here are for Triumph unit 500/650s. Apparently, connections for pre-unit Triumphs are the exact opposite.
In the following descriptions of oil line connections, 'front'/'forward' and 'rear'/'back' use the front and back of the motorcycle as a reference.
On Bonnie (NC00125) without an oil filter:
Or put another way, 'back to front and front to back.'
Bonnie's Norton oil filter head is installed in the return oil line as per the following diagram.
A 3/8" plastic tube (70-5375 Ref# 39 Fig.2 #7) connects the engine breather pipe stub (70-2724 Ref# 7 Fig.2 #7) just forward of the gearbox sprocket to Tee (70-5370) near the top of the oil tank. Also connected to the tee is the oil tank vent pipe ( 70-6356, Ref# 16 Fig.23 #7), and the oil breather vent tube (82-7353, Ref# 18 Fig.23 #7) which leads to the mayonnaise dispenser at the back of the rear fender.
The oil breather vent tube passes on the left side just above the indentation in rear fender.
The first clamp is fastened on the left-hand side beneath the left nut holding the strap on top of the fender between the two upper shock mounts.
ResourcesWorkshop Manual (1969 650cc Twins) Section B33: Remove/Replace Oil Pump
Although Triumph made several changes to 650/750 oil pumps, all the pumps are interchangeable (John Healy).
|1963 - 1966||E3878||Scavenge 0.437"/ Feed 0.374"|
|1967 - Early 1969||E6928||Scavenge enlarged to 0.487"/ Feed 0.374"|
|Late 1969 - 1979||E9421||Scavenge 0.487"/ Feed enlarged to 0.406"|
|1980 and on||71-7317||
Double check-valve pump
(Scavange& Feed unchanged: Scavange 0.487"/ Feed 0.406")
Source: Britbike.com thread "Oil Pump Confusion Unit 650cc SOLVED!":
ResourcesWorkshop Manual (1969 650cc Twins) Section A5: Oil Pressure
Dome nut - 15/16" wrench. Nut behind it - __?__.
ResourcesWorkshop Manual (1969 650cc Twins) Section H18: Oil Pressure Switch
I have on hand a custom made blanking plug from Walridge for the oil pressure switch that I'm not using on Bonnie. I have never installed it because of concern about whether or not its threads match those in the timing cover. I've read that the casing threads were, at one time, tapered. Putting an untapered plug into a tapered thread hole is said to possibly split the casing. See discussion above.
ResourcesWorkshop Manual (1969 650cc Twins) Section B19: Removing and Replacing the Cylinder Block and Tappets
ResourcesBritbike.com "Which Comes First, Piston or Bore?"
Before having a shop hone the cylinders, or doing it yourself, see these links for John Healy's tips on honing and 'dry' ring assembly. It's about getting a good break-in.
ResourcesBritbike.com "Re: L F Harris Pistons/Rings" (honing cylinders)
After cylinders have been honed, wash them with detergent and hot water to remove all abrasive materials left behind. Then wash them again. And again. Foreign materials left behind may score the cylinders or block oil-ways. When thoroughly clean, dry the cylinders with a clean cloth and then apply light coat of oil.
ResourcesWorkshop Manual (1969 650cc Twins) Section B21: Renewing the Tappet Guide Blocks
To remove or replace the tappet guide blocks it's essential to use the special drift: Service Tool 61-6008. It takes substantial blows with something like a little two-pound sledge to drive the blocks in. While a block is moving, it can be steered quite easily by twisting on the tool's hatch-marked handle.
When driving the guide blocks in or out, remember that they are not perfectly vertical - they are set at a slight angle. Adjust your drift accordingly or risk damaging the block's skirts. Ask me how I know.
On his DVD, Hancox says to line up the hole in the blocks with the locator screw hole in the cylinder block. For an amateur like myself that's not a sufficient guarantee that the tappet holes will end up exactly parallel to the camshaft. Instead I try to concentrate on the alignment of the tappet holes with the camshaft - if that is acheived the locator screw will line up for sure.
Being relatively narrow, the tappet blocks are difficult to line up perfectly by eye. For best results, use a straight edge placed against the block.
New guide blocks frequently require honing before the tappets will ride up and down freely.
For the exhaust tappets to be properly lubricated, they must be installed in the tappet block with their "flats" ("C" in illustration at right) facing outward.
Removing old gasket material is an annoying job. Using a gasket remover product is probably a much better alternative than scraping with razor blades. Loctite makes two such products 1) Loctite 'paint remover', and 2) Loctite 790 'Chiselr Gasket Remover'. Afterwards clean the surfaces with acetone.
Can't get on the block nuts with a torque wrench, but using a 6-inch 12-point box wrench (1/2") to tighten them as hard as possible will approximate the proper torque of 35lbs.
ResourcesBritBike.com Cylinder paint recommendations?.
Unquestionalably, the best-looking and longest-lasting finish for the cylinder block is powder coat. For tips on other products and surface prep see link above.
ResourcesWorkshop Manual (1969 650cc Twins) Section B38: Refit Connecting Rods
ResourcesWorkshop Manual (1969 650cc Twins) Section B22: Removing and Refitting the Pistons
To remove gudgeon pins, heat pistons to around 100C. In 2006 I used way too much heat, so in 2016 I monitored the temperature using the digital laser thermometer. Also in 2016, I first packed snow in plastic bags around the pistons to chill the gudgeon pins before heating the pistons.
In 2016 I was able to push the first pin most of the way out but it wouldn't quite make it all the way. I fashioned a little extractor tool out of a threaded rod, a 3/4" pipe nipple, a short piece of 1/2" copper pipe, and a couple of nuts. (Below, right).
Chill gudgeon pins and, if necessary, heat the pistons. In 2016 I only chilled the gudgeon pins and they slid quite easily through the pistons and the small ends. I thought this was too easy, but the WS-Manual says that's how they should go in.
ResourcesWorkshop Manual (1969 650cc Twins) Section B23: Removing and Replacing the Piston Rings
Installing rings is pretty straight forward - always from the top and be sure to observe correct order and cylinder for each ring.
Orient the oil scraper rings with their gaps at six o'clock, and the compression ring gaps at three o'clock and nine o'clock.
One advantage of using ring compressors is that the orientation of the ring gaps doesn't change during installation.
ResourcesWorkshop Manual (1969 650cc Twins) Section B14: Removing & Refitting the Cylinder Head Assembly
I think Bonnie's head has been very lightly skimmed, but I'm not sure. I have no way to measure its height, and anyway, published specs for that vary, as probably did the heads themselves.
With only a propane stove or propane torch for heating, I can't heat the entire gasket cherry red to plunge vertically in deep water. Instead, I anneal it section by section. This creates more surface oxidation.
John Healy says that removing surface oxidation left behind by annealing makes for a more professional-looking job. In 2016, the first time I annealed the head gasket, I scrubbed off the oxidation with copper cleaner (lots of work). After the second time I annealed the gasket I let it sit in vinegar overnight. Nearly all the oxidation turned to a brown 'fluff' that rinsed off easily, leaving the gasket 95% bright.
Before installing a head gasket, remove any burring from the head gasket. Burrs, it's said, can become hot spots and cause pre-detonation (pinging).
Apply either grease or Permatex copper to both sides of head gasket before installing. I used the Permatex copper during both head assemblies in 2016. Using a sealing agent will help prevent a) oil leaks, and b) compression leakage between the cylinders.
During 2014/2015 oil was leaking from somewhere on the top end and flowing down the rear of the cylinders, especially the drive side, until it wound up pooling on top of the gearbox.
When I re-assembled after Jan-Mar 2016 top end refresh that leak was gone, but it was replaced by an oil leak from the cylinder base. My last gasket had a bit of a tear on one side, and rather than wait for a new one, I'd used it anyway.
In June (69,575 mi.) I removed the head and cylinders a second time and used Coventry Spares gaskets (from Baxter) for the cylinder head and the rocker boxes (with wire).
Should also note that during first 2016 assembly I used Hypolar on base and rocker box gaskets. I wouldn't do that again. On the second assembly I used grease as I always had. Another option would be a sealant like Loctite 515.
Note: 3,000 miles later and no leaks to date - May 2017 (72,500).
For head bolts and spark plugs I think the anti-seize compound is a good idea. However, when it has been used, it's extremely important to thoroughly clean all threads before reassembly.
A method that works well is to first swab out the bolt holes with Q-tips and then fill them with kerosene. Then run bolts in and out, using a rag to mop up the kero and all the crud as they squeeze out. Repeat using brake cleaning fluid.
Over the years considerable confusion has arisen about correct torque figures for 650 Triumph head-bolts. The confusion is between 15/18 lb (correct) and 18/25 lb (erroneous). According to John Healy, it all eminated from the 1966 Triumph Workshop Manual, whereafter it was possibly printed several times without correction. The figures below are the correct conventional settings.
Torque figures given are for dry threads. One recommendation is reduce by 20% when wet. So for example, if using anti-seize compound, one would use 15lbs instead of 18. When I've used anti-seize compound I confess I've still used the 18 lb figure.
The head bolts are tightened in the order 1-2-3-4-5-6-7-8-9 as shown in the accompanying illustration, and the final torque rating is reached by incremental steps. For example, tighten all the 18 lb torque bolts to 10 lb, and then 14 lb, and finally 18 lb.
On his DVD, Hughie Hancox starts with bolt #1 and tightens each bolt one by one right to their final torque figure. I tried that method in 2006 and it worked ok, but I feel more comfortable using the incremental 'round robin' method.
The 1/4 inch rocker box bolts and the rocker box stud nuts are torqued to just 5 pounds. Be careful. Install bolts and nuts at least finger tight before torquing head bolts. Doesn't hurt to tighten these fasteners incrementally among themselves and in conjunction with the head bolts. In the end the three nuts can be loosened slightly and re-tightened to obtain an identical torque.
After the first heat cycle(s) when the head has been removed and replaced, the head-bolts must be re-torqued to compensate for their looseness due to the "bedding-in" of the cylinder gasket, cylinder head, and bolts.
Because torque figures pertain to bolts when they are turning, it's not effective to just start tightening them. That would most likely result in over-torquing, which is never a good thing. So, the method is:
Note that the bolts don't actually loosen themselves, they loosen relatively, due to compression of the head gasket and stretch of the headbolts. Nevertheless, the question arises in many minds, were the bolts actually "loose" before re-torquing, and if so by how much? One way to find out is to mark one point of each headbolt and then make a corresponding mark on the head. After you re-torque you'll see whether it was necessary to re-tighten each bolt.
And as the "Duke of Oil" pointed out on Britbike.com, given their thread factor and how far the bolts turned to get back to spec it's possible to calculate how much the head gasket compressed and the head bolts stretched.
If you're ever tempted to try cleaning up a Triumph cylinder head with oven cleaner, think twice lest the head winds up looking this way. It took bead-blasting to remove the resulting corrosion.
There's no substitute for rags and q-tips and kerosene and brake cleaner and elbow grease.
ResourcesWorkshop Manual (1969 650cc Twins) Section B2: Removing and Replacing the Rocker Boxes
ResourcesTriumph Service Bulletin #25 "Lubrication - Rocker End, Ball Arm"
Thackary. As pointed out by one BritBike.com poster: rhymes with 'quackery'. And have you ever wondered how Thackary washers got their name? Ian Peters on "More To The Name" has quite an interesting story about its origins. But I digress.
Starting from TS, the original #7 layout used with plain rocker spindles
The updated layout for use with grooved spindles & notched rocker arms:
Not strictly necessary to remove the ignition coils, but we want to polish them up anyway, right? After removing gas tank, torque stays, and the domed nuts and copper washers from the oil lines, gradually release the torque from and remove:
As per WS and Hanyes manuals, I used a 5/16" bolt ground to a taper at one end to help line up the flat and spring washers before inserting the spindles. With enough fiddling around they eventually go on.
If a spindle doesn't go quite all the way in it is probably due to the last washer (DS) hanging up on the rocker spindle's shoulder. Play with the washers and tap very lightly on the end of the spindle with plastic mallet. When everything is lined up it takes only a light tap.
ResourcesEd Holin "What is the correct O ring for the rocker spindles on a '71 Triumph T100R and similar bikes?".
When replacing the rocker shaft o-rings (ref#29 Fig.5 #7), don't use the 70-3253 listed in #7. Use updated, better fitting part 60-3548. And be sure it's Viton.
For what it's worth - special tool Z111, rocker spindle oil seal compressor, is available. I've never found it effective or helpful.
ResourcesFig.5 Pushrod Tubes
Two different pushrod tube designs were used between 1968 and 1973 on "B" range 650 machines:
Bonnie, a 1969 model year built in Oct 1968, has the one-piece design.
ResourcesTriumph Service Bulletin #18-69 "PRT o-rings leaking oil - 1969 'B' & 'C' Range"
Oil leaks from the pushrod tubes are a perennial problem for many Triumph owners. In 1971, Triumph specified a red, high-temperature o-ring (E111283) for use on top. They were supposed to resist the higher temperature between the exhaust PRT and the cylinder head. I tried the red o-rings twice and found that they crumbled pretty quickly both times.
Later, the 71-1283 o-ring became available in Viton, and Viton is the only way to go. On Bonnie I use 71-1283 o-rings in Viton top and bottom and they have never leaked appreciably. (Knock on wood).
The following table details the different PRT o-rings used between 1969 and 1971.
|#7 ('69)||'70 USA||'71 USA|
Triumph Service Bulletin 324 Pushrod tube oil seals
Pushrod tube oil seals were a modification introduced by Triumph around 1971. These oil seals are at the bottoms of the PRTs, between the PRTs and the tappet guide blocks.
For a better seal, the upgrade uses a square-sectioned sealing ring retained by a metal band (the "wedding band") at the base of intake and exhaust PRTs.
The square-sectioned sealing rings are commonly, but not always, white silicon. I've had black, sponge-like seals and they worked fine. These seals come in different thicknesses to enable adjustment of "the crush". (See section below).
Bonnie's been upgraded to the parts shown in Figure 4 of the Triumph '71 USA parts book.
ResourcesJohn Healy, Vintage Bike Magazine "Push Rod Tubes"
Note: this section updated 5 June 2019 to reflect the proper usage of the term 'crush'.
'Crush' refers to the amount of compression of the seals and o-rings at the bottoms and tops of the PRTs respectively when the head bolts are tightened down. Too little crush means the seals are compressed insufficiently to create a good seal, resulting in oil leaks. Too much crush results in the seals holding the cylinders and the head apart and further tightening of the head bolts can cause the alloy head to warp.
When the head is sitting freely (loose bolts) on top of the cylinders with the head gasket and PRT seals and o-rings in place, there should be between .030" and .040" gap between the cylinder head and the head gasket.
If the gap is too wide there will be insufficient crush, resulting in a poor seal and oil leaks. If the gap is too narrow there will be too much crush, risking distortion of the head when head bolts are torqued down.
The gap, and therefore the crush, are adjusted by substituting different thicknesses of sealing rings. A thicker sealing ring holds the PRTs and the head higher, increasing the gap and reducing crush. A thinner seal makes the gap smaller, increasing the crush.
For dimensions of sealing rings & o-rings see table below.
Install head with bolts 6,7,8,and 9 fitted evenly and lightly enough that the bottom seals and top o-rings are not being compressed. Then check for a suitable gap that is even all the way around.
Although one of Bonnie's pushrod tubes seats very tightly at the bottom and the other is relatively loose, they both seem to seal well to the tappet block once the head is bolted down and the sealing ring squashes out to the wedding ring.
Be sure to oil the top and bottom o-rings before assembly (sharp edges ahead). It's also ok and good to grease the top o-rings to help hold in place as well as lubricate.
In 2016, I used 'Right Stuff' on the top o-rings during first assembly. Upon disassembly 450 miles later, I picked the Right Stuff 'slime' out of the o-ring groove. No more 'Right Stuff' for me. Back to oil and grease.
When installing the head, it may go better to maneuver it into place from the rear, as opposed to from one side or the other.
Slight in & out adjustments (punch and ball peen) to the tabs at the top of the PRTs can sometimes ease installation or removal of the PRTs. Just be sure the tabs don't foul the pushrods when they are installed.
When adjusting for proper sealing ring crush, the following dimensions could be helpful.
2.785 (Internet forum)
|Round o-rings||70-7310 (Buna-n) / 71-1283 (Viton)
ID=.987"/Nom 1" CS=.103"/Nom 3/32" OD=1.193"/Nom 1 3/16" Dash#120
|Square-sectioned sealing rings||
71-1190 Thick= .033" (Raber's)
70-3547 Thick= .093"/nominal 3/32" (.091 Raber's)
70-4752 Thick= .125"/nominal 1/8") (.123 Raber's)
70-1496 Thick=.1875"/nominal 3/16" (.177 Raber's)
Source: unless otherwise noted, dimensions are from John Healy's article 'Push Rod Tubes' in Vintage Bike Magazine.
ResourcesBritbike.com "Gasket sealer for top end "
I've used wire-reinforced (BCS and Walridge), plain paper (MAPCycle), and paper & metal sandwich Covseals (Baxter) for rocker boxes. Covseals made the best seal, followed by MAPCycle's plain paper. Wire-reinforced gaskets were my least favorite.
I used the Covseals dry as per included instructions and I noticed some weeping. After reading the BritBike.com post just above I coated the Covseals with Hylomar the next time and the rocker boxe joints were completely leak-proof.
ResourcesWorkshop Manual (1969 650cc Twins) Section B2: Removing and Replacing the Rocker Boxes
I label the push rods with a marker when I remove them & replace in their same position. If I remember, else not. As I replace the push rods I examine them and, ideally, make note of anything special, such as wear to the cups.
When I tried using lightweight pushrods it was necessary to modify the rocker box gaskets to accommodate their larger diameter. After modification the gaskets no longer served to guide the pushrods to the rockers when fitting the rocker boxes, so I made a template to guide the pushrods, split it in two, taped it back together for assembly, and removed in two pieces when the rods were placed.
The banjo fittings on the rocker oil feed pipe connect to the rocker spindles with domed nuts. Prior to 1973 the domed nuts were 3/8-26TPI, but they were changed to 24TPI UNF in 1973. If you're having trouble threading on replacement domed nuts, suspect a thread mismatch between the nuts and the spindles.
The four copper washers should be annealed prior to replacing. The WS Manual gives a torque spec of 22 lbs for these nuts.
TRV7RMan on Britbike.com: "I don't go 22# on torque on these. It just seems too tight. I do it by feel. I've had practice though."
"Not a bad plan to put some sealant on washers also. Loctite 518 is my sealant of choice, however Hylomar universal blue or any of that family of hylomar will work good also. Put a thin smear both sides. Wipe hole of washer clean. Hang washer on wire 10 min to flash of solvents in sealer. Handle washer from outside. Assemble & tighten acorn nut. Make sure you don't smear sealant on threads or shaft sliding washer on. Clean box surface, banjo sides, nut face well & dry. Sealant doesn't stick well on oily surface. Wipe off excess quickly."
"If banjo fittings want to spin when tightening nuts, counter hold them on the flats. Don't let them spin & bend tube."
ResourcesFig.14 Engine Torque Stays
Note that in the video above, Lunmad uses a slightly unorthodox method to open valves for adjustment.
For example, instead of, as per the WS Manual, opening the DS exhaust valve (pushrod up, rocker down) to adjust the TS exhaust valve clearance, Lunmad closes the TS intake valve.
Tip When checking or adjusting valves with the gas tank on the bike, Lunmad's method makes it much easier to adjust the TS exhaust valve.
ResourcesWorkshop Manual (1969 650cc Twins) Section B15: Remove/Replace Valves
Install valves, springs, and retainers as per figure at right. Use red valve spring compressor and grease the split collets to help hold the first in place while inserting the second one.
ResourcesWorkshop Manual (1969 650cc Twins) Section B5: Adjusting the Valve Rocker Clearances
When adjusting the valve rocker clearances, it's better to have a tiny bit too much clearance between the valve stems and rockers than not quite enough. Too little clearance and the valves may burn because they cannot fully close once the engine is hot. On the other hand, too much clearance means the rockers will 'hammer' the valve stem tips.
Note that after the rocker boxes, head, and/or cylinders have been removed and replaced, or any time the head bolts have been re-torqued, it's important to re-check the valve rocker clearances after a very brief run-in. All the conditions above will compress the gaskets and therefore decrease the clearance between valves and rockers. Symptoms of this include excessively high engine temperature, loss of engine power, and low compression due to the exhaust valves remaining slightly open.
Sound can be a useful guide to setting valve rocker clearance (see 'Adjustment by sound and feel', just below), as well as when evaluating correctness of settings with the engine running.
It's much easier to adjust valve clearance while the carburettors are removed, but adjustment can also be done with just the gas tank and air filters off. And by the way, if you got carried away tightening the valve inspection caps the last time and are having trouble getting them off, gently heating the rocker box cover around them will make them loosen right up.
When TR7RVMan speaks, I listen, so although I've never experienced the problem he outlines in this TriumphRat post, I may adopt his method of preventing it. TR7RVMan:
"One little thing that can happen is you remove spark plug & some carbon breaks off from threads. It gets trapped in valve seat & holds valve open slightly. You feel clearance & it's loose so you adjust to spec. Starting motor the carbon blows out of seat, now valve is fully closed leaving it too tight.
Triumphs can/will do this, but are not prone to it. (some motors are very prone to this). The cure is don't remove spark plugs before valve adjustment even though motor is hard to turn over. Or... Loosen plugs 1 turn, reinstall plug caps & start motor. Blip throttle several times to like 3000 rpm. Remove plugs, let motor cool all day or overnight, then adjust valves. Either of these assures carbon will not interfere with accurate valve adjustment."
The stock Trimph adjustment pins have square heads which make adjustment quite vague. If you're using the square-headed adjustment pins you may want to check out the two-piece valve adjuster tools that are available. In theory these should make adjustment a snap because they allow you to control adjustment with thumb and finger while simultaneously tightening or loosening the locking nut. In practice, the fit between the adjustor and the square pin is too sloppy to give good control.
I find the readily available adjustment pins with hex heads are a big improvement as they make it easier and more accurate to gauge the degree of change in adjustment. With these pins you get good control with an allen head wrench handle as you tighten or loosen the adjuster pin locknut with a short 7/16" box-end wrench.
Valve clearances should be set to .004" for exhaust and .002" for the intakes. A common method of obtaining 'ballpark' settings is to run the adjustors in until they just contact the valve stems by feel, and then back them off 1/8 of a turn for exhaust, and 1/16 turn for intake.
Another common adjustment method is to grasp the rockers with thumb and index finger and rock them up and down:
In order to adjust a valve's clearance, the valve must be closed. To position a valve in its closed position (rocker up), make the opposite valve fully open (rocker down).
Formally, I had difficulty getting consistent valve clearance measurements, probably due to inaccurate positioning of the valves. I've improved this in two ways: using the rear wheel instead of the kickstart lever to do the fine positioning, and by using a finger to gauge when a rocker has reached to lower limit of its travel.
So, to adjust the DS exhaust valve, make it closed by opening the TS exhaust valve as follows:
On adjusting the clearances:
When head has been removed and replaced, valve clearance needs to be re-adjusted several times due to gasket 'crush'.
ResourcesYouTube Lunmad: Compression Test
Testing engine compression is a quick and easy way to determine an engine's general health with regards to valves, rings, and cylinders.
Five easy steps:
If compression is low, add small amount of oil to the cylinders and retest.
If valves are suspected, check to ensure there is adequate valve clearance to prevent valves from closing fully.
ResourcesBritBike.com "1969 T120R magically loses compression"
A sudden loss of engine compression can result from gas washing the pistons. In August of 2018, after sitting for ten days, the Bonnie seemed to give up all compression after the first kick. TR7RVMan on BritBike.com correctly diagnosed the problem and offered a solution which consisted of pouring a couple of tablespoons of oil down the plug holes, kicking over the engine several times with the plugs out to remove excess oil, replacing the plugs, and starting as usual. The method worked perfectly and normal compression was restored as soon as the bike started. And no problem during the following days.
|Year / Mileage||Cylinder||Opp Plug In||Opp Plug Out|
|2016/68,500mi - 3 heat cycles after top-end job||Left||120|
|Opp Plug In||With Oil|
|Opp Plug In||Opp Plug Out|
|2006/Frank's - After break-in||Left||165-170||-|
|2006/28,600mi - Right after top-end rebuild||Left||135||-|
ResourcesWorkshop Manual (1969 650cc Twins) Section B32: Remove/Replace the Timing Cover
ResourcesWorkshop Manual (1969 650cc Twins) Section B34: Extract/Refit Valve Timing Pinions
The difficulty in removing the nut securing the crankcase pinion gear is keeping the gear from moving. That is the topic of discussion in this BritBike.com thread. In it, a solid group of posters propose and debate a variety of methods:
For a novice mechanic like myself, the 'jamming the gears' techniques have too much potential for disaster, even though they may be ok in more experienced hands. Similarly, barring the small ends may not be quite as simple as I have always thought.
I will definitely try remembering to loosen the pinion gear nut FIRST next time. I'll also try remembering first to put the gearbox in neutral and try the impact wrench to see how well that works.
ResourcesWorkshop Manual (1969 650cc Twins) Section B35: Valve Timing
ResourcesWorkshop Manual (1969 650cc Twins) Section B36: Dismantle/Reassemble Crankshaft Assembly
ResourcesWorkshop Manual (1969 650cc Twins) Section B37: Stripping & Reassembling the Crankshaft Assembly
The sludge trap is a metal tube fitted inside the gallery that runs through the big end rod journals. Oil is forced through the timing end of the crankshaft and through oil passageways into the sludge tube. There, centrifugal force separates dirt suspended in the oil - think of a washing machine's spin cycle with all those bras and panties flattened out against the inside while the water flows away. Inboard weep holes permit the oil to lubricate the big end bearings and then return to the crankcase sump from where it's pumped back to the reservoir.
Although it's controversial and frequently maligned, the Triumph sludge trap is actually a relatively effective oil filter. It's big drawback is that it can't be inspected or cleaned without splitting the crankcase - a major job requiring complete disassembly of the transmission and engine, but not necessary the gearbox.
Some believe that no matter how full the sludge tube becomes, oil under pressure will always make its way to the big ends.
That's a theory, but the more widely accepted notion is that a plugged sludge tube will prevent oil from flowing to the big ends with catastrophic results.
It's also widely held that after a bike sits for a long time and is then restarted, dirt particles in the tube may break off and subsequently block critical oilways in the engine, there being more risk for machines lubricated with non-detergent oil before storage and then drained and re-filled with detergent oil before re-starting.
So without splitting the cases, how does one know whether or not the sludge tube needs cleaning/replacing? Unfortunately we can't answer this question precisely, we can only make an educated guess based on service history and engine condition.
|More Sludge Deposits||Fewer Sludge Deposits|
|High mileage||Low mileage|
|Using non-detergent oil||Using detergent oil|
|Running dirty oil||Frequent oil changes|
|No external oil filter (as stock)||Fitting external oil filter|
Mileage alone is not necessarily a reliable indicator, but I've heard suggested a service interval of around 40,000 miles. But keep in mind that there have been bikes whose sludge traps were found to be full or nearly full at lower mileages than that.
At the end of 2019, my Bonnie had 81k miles. The sludge tube was replaced at 44k miles. Using the 40,000 mile rule it would soon be time for cleaning. However, I installed an external oil filter at 43k miles, and I change oil every 1,000 miles, so unless and until other crankshaft work needs doing, I doubt that I'll be too concern with cleaning the sludge tube.
It has been suggested that sludge traps on '70 and onward 650 Twins possibly fill up more quickly because those models share oil between the primary chaincase and the crankcase, and, it's assumed, the clutch produces more sludge (think shock absorber rubbers) than the engine itself.
Sludge tubes can be quite difficult to remove as there are two hurdles: removing the cap, and removing the tube itself. Tubes don't always survive the extraction, caps rarely. However, replacement sludge tubes are not expensive. Also, caps for them are now available which have either hex heads or hex key sockets instead of the more difficult to remove slotted head on the stock item.
There are two ways to remove the tube: smack it out and pull it out. Pulling it out may contribute to higher rates of tube survival. More later.
What size tap to use for (smack it out) tube removal? LowBrow video (link above) suggests 3/8"-18 N.P.T.
When replacing the sludge tube be absolutely certain that its alignment hole is actually lined up for the flywheel bolt before inserting and tightening the bolt (Grand Paul).
ResourcesWorkshop Manual (1969 650cc Twins) Section B40: Renew Main Bearings
ResourcesHermit.cc Hermit's Illustrated Ignition Timing with Points Complete instructions for static and dynamic timing using points.
Note that the timing mark on Lunmad's 650 rotor corresponds to TDC. On Bonnie the timing mark corresponds to 38 degrees BTDC. As mentioned by Lunmad in the comments section, use the flywheel locator tool to determine which location the timing mark on your bike's rotor represents.
ResourcesHermit.cc Hermit's Illustrated Ignition Timing with Points Complete instructions for static and dynamic timing using points.
The contact breaker points gap for late-60s 650 Triumphs is .014-.015-.016".
For clearly illustrated instructions on setting ignition timing with points see "Hermit's Illustrated Ignition Timing with Points". Also be sure to read TR&RVMan's superb post on points ignition timing.
ResourcesPazon installation, timing, and trouble-shooting
Use a flywheel locator tool (OR timing pointer and rotor timing mark if the one on your rotor points to 38 degrees BTDC and not TDC) to locate 38 deg advance.
Use strobe on either cylinder for dynamic timing
It would probably be helpful to establish corresponding reference marks on the Pazon disk and the timing cover.
If the cover is installed on the chaincase before screws are inserted, mating the first screw to the threads in chaincase can be annoying. Easier to find the hole by inserting the top screw in the cover and fitting both together dangling from a Phillips screwdriver.
Use Metric M8 bolt threaded into rotor.
ResourcesWorkshop Manual (1969 650cc Twins) Section H3: Sparking Plugs
Used NGK for quite a while, but have returned to using Champion N3C (new Champion designation 801).
Plug gap: .025".
Interpreting NGK plug designations:
B= 14mm plug thread
7 = Temperature range
E = 19mm plug thread reach
S = Standard super copper core electrode
The higher the NGK number, the colder the plug
The lower the Champion number, the colder the plug
ResourcesWorkshop Manual (1969 650cc Twins) Section B13: Removing and Replacing the Exhaust System
I have Bonnie's original headers with crossover pipe in inventory, but I replaced them with non-crossover types on the bike.
When removing the exhaust header pipes and mufflers, remove them as a unit on each side. Simply remove or loosen the exhaust pipe clamps, the exhaust pipe engine bracket Phillips heads screws, and the muffler hanger bracket bolts.
When removing or replacing the exhaust pipes over the exhaust pipe adaptors (spigots), it's ok to hit them with a plastic mallet as long as you place a thick, folded rag over the pipes and don't go crazy.
ResourcesWorkshop Manual (1969 650cc Twins) Section C: Transmission (TOC)
The primary chaincase houses the transmission, which consists of the engine sprocket, the primary chain, and the clutch assembly. The transmission's job is to transfer energy from the engine sprocket to the gearbox mainshaft, the gear cluster, and subsequently to the gearbox sprocket and rear wheel.
See Lubrication Schedule, Primary Chaincase
BritBike.com 'Primary Case removal'
If your primary chaincase cover is good and flat, try this tip: put gasket sealer on the side of the gasket that goes to the cover and grease the side that goes to the chaincase. Chances are that the next time you remove the cover the gasket will stay on the cover and you can re-use it upon re-assembly.
If you're having difficulty removing the chaincase cover, or keeping the gasket in place while putting it back on, have a look at this thread on BritBike.com:
ResourcesWorkshop Manual (1969 650cc Twins) Section C2: Adjusting the Primary Chain
The WS Manual method to check wear in a primary chain:
Excessive tightness of the primary chain can damage the DS crankshaft bearing, the chain tension slipper, clutch components, and/or the gearbox mainshaft and its bearing. Coversely, too much slack can give rise to some bad-assed noises from the primary chaincase, not to mention damage to the stator or the primary case itself due to rubbing.
The WS Manual specifies 1/2" total up-and-down slack in one place, and 3/8" in another. Although this ambiguity is often regarded as an error, it might also be interpretted to mean that the correct adjustment may vary. Like drive chains, primary chains will vary in tension from one position of the chain to another. Therefore, rotate the chain and check tension in multiple positions until you find the points of greatest and least slack.
In order to adjust the primary chain tension, the oil must be drained from the primary chaincase, so it's only logical to check the tension at each oil change and adjust if necessary.
ResourcesWorkshop Manual (1969 650cc Twins) Section C3: Removing and Replacing the Primary Cover
The clutch assembly, engine sprocket, and primary chain are removed simultaneously as one after slacking the chain and removing the stator and rotor.
Exploded figures with parts numbers and specs:
Rotor nut torque was about right, rotor pulled right off by hand. Once again, the 'self-locking' clutch nut not very tight. Will put the blue to it this time. Kickstart ratchet nut was good and tight, not excessively. Engine sprocket, clutch wheel/center all popped off easily with their respective tools.
Things looked pretty good this January when I tore apart the transmission and gearbox. The primary chaincase and clutch assembly were still quite clean. There was some gray (metal) in the gearbox.
Possibly some wear evident:
Things that were kind of loose:
In 2016 I began carefully tightening down the extractor tool and just as I was getting ready to stop and give it a whack with the brass hammer, the center popped off the () mainshaft. Not surprising as the taper on that shaft was very pitted.
The extractor tool only engages the clutch center threads by about a half-inch and in 2015 I stripped its threads.
When a replacement tool arrived, I applied WD-40 to the clutch center and 'pre-stressed' it with the new extractor for a couple of days.
When it still wouldn't release, I tapped against the inside of the clutch center with an aluminum drift. Then I tried striking the "loaded" extractor tool with a brass hammer. Still nothing moved.
Finally, after researching BritBike Forum, I tried the air wrench. After about 20-30 seconds of gentle hammering at the wrench's lowest setting, the center released from the mainshaft.
That's when I saw that the main shaft/clutch hub key had sheared off length-wise. I also noted that the clutch hub had spun on the mainshaft.
ResourcesWorkshop Manual (1969 650cc Twins) Section C10: Inspection of the Transmission Components
TR7RVMan states that a genuine Triumph clutch stack will measure 'very close' to 1.400", while an Aerco 7 plate clutch with all new steels will measure 1.380".
ResourcesBritbike.com John Healy: Thrust washer/clutch center compatibility
The original clutch center (57-1734) uses the 57-1735 thrust washer. Bonnie was upgraded in 2015 (65,000 miles) to use an upgraded thrust washer (57-3931) and clutch center (57-3929).
These parts are not mix-and-match as the inner diameter of the thrust washers are different. It's easy to tell if a thrust washer is made for a particular clutch hub - the ID of the thrust washer should fit the matching recess in the hub.
Both thrust washers (57-1735 and 57-3931) are, or were, available in different materials:
For thrust washers with one side copper and one side steel, place the copper side towards the clutch basket.
The spec given by the manual for thrust washer thickness is .052/.054". Some shops (MAP among them) supply thicker washers, but there are reports that too-thick a washer can cause the clutch pack to lock up when the clutch center locking nut is tightened.
ResourcesWorkshop Manual (1969 650cc Twins) Section C7: Renewing Shock Absorber Rubbers
See Sprocket Alignment note just below.
Don reminds us that if it's a pre-unit model both the first and last clutch plates are steel, while on unit model clutches the first plate installed is friction and the last plate is steel.
ResourcesWorkshop Manual (1969 650cc Twins) Section C6: Adjusting Clutch Pressure Plate
Three adjustors permit adjustment of the pressure plate until it lifts and falls evenly and compresses the clutch plates evenly all around.
After initially setting the adjuster nuts flush with the ends of the adjuster screws, use a pressure plate spring adjustment tool to adjust the three pressure plate spring adjustment nuts to eliminate wobble of the pressure plate as it turns.
To check for wobble, pull in the clutch lever to raise the pressure plate and then turn the clutch using the kickstarter. Observe the outside edge of the pressure plate for wobble as it goes around and use the spring adjustors to compensate for uneveness.
RancidPegWoman uses the clutch rod adjustment screw to raise the pressure plate. Great tip!
Wobble can be guaged by eye, but a pointer is a great help and can be as simple as a piece of coat hanger wire and some duct tape.
After adjustment, make final check is to see that the pressure plate lifts evenly all around when pulling in the clutch lever.
Properly adjusted, clutch spring tension should be a happy medium between too loose (clutch will slip) and too tight (excessive hand pressure required to operate the clutch and possibility of damage to the clutch rod). If the coils become bound or the spring tension otherwise too high, loosen the three adjustors by small, equal amounts at a time until spring tension is eased and then re-check wobble.
ResourcesWorkshop Manual (1969 650cc Twins) Section C1: Adjusting the Clutch Operating Mechanism & Cable
The Rabers' video well demonstrates the standard WS method:
The procedure is pretty straight forward, but there are a couple of tips and techniques for best results.
To begin with, it's essential that the clutch cable is completely slack before beginning the adjustment. If not, there's a good chance the 3-ball clutch operating mechanism in the outer gearbox cover will wind up out of its adjustment range - see "Clutch Operating Mechanism Pops or Clicks" just below under "Clutch Problems".
Stuart gives us a technique to determine exactly when the clutch rod adjustment screw contacts the clutch rod. He uses just a thumb and a finger to lightly hold the screwdriver as he turns the screw in. When the screw and the rod meet the screwdriver will stop.
Guys use different methods to hold the adjustment screw stationary while the lock nut is tightened: many use a screwdriver through a socket and tighten the nut using vicegrips on the socket (but be kind to your sockets and use a rag). Those who have one use a special offset hollow-head socket wrench through which they can insert a screwdriver. DMadigan has a very simple and clever method: he simply pulls in the clutch lever to load the screw with tension while he tightens the nut!
Whichever method you use, eyeball the adjuster screw head position before and after tightening down the locknut to be sure it didn't move.
As pointed out by TR7RVMan, new clutch plates will decrease in thickness as they 'bed down', and as the thickness of the clutch pack decreases so does the clutch rod clearance. When the clutch rod clearance becomes less than zero, clutch plates get held apart resulting in the clutch slipping and possibly burning out. So, when adjusting a clutch with new plates, provide slightly additional clearance - something between 3/4 turn and the WSM full turn, and then be sure to check the adjustment regularly until the plates are broken in.
ResourcesWorkshop Manual (1969 650cc Twins) Section D7: Clutch Operating Mechanism
See Clutch Problems, '.. Pops or Clicks' immediately below.
If a popping or clicking noise occurs when pulling in the clutch lever it means the 3-ball clutch operating mechanism in the outer gearbox cover is out of its adjustment range. This occurs if the clutch rod is under-adjusted (too much slack) and the cable adjustment is over-adjusted in compensation. That combination of poor adjustment advances the static position of the clutch operating mechanism until normal operation of the clutch lever/cable forces the mechanism past it's designed operating range. When that happens the steel balls click and pop as they pass the ends of thier ramps.
All that's necessary to correct the condition is to properly adjust the clutch operating rod and the clutch cable as described above.
It's been said that the crunching sound made when selecting first gear from neutral has a Triumph part number. Not quite, but it is very common. Usually the problem is clutch, not gearbox. Some common causes of 'the crunch' and ways of reducing it:
ResourcesWorkshop Manual (1969 650cc Twins) Section D: Gearbox (TOC)
|Hermit.cc Index to all 8 of Hermit's Illustrated Gearbox Articles|
ResourcesHermit.cc Stills, Rear View
See Lubrication Schedule
ResourcesTriumph Service Bulletin #329 "Third gear ratio and selector forks modifications"
The problem of jumping out of 1st gear plagued Bonnie for over two years. Eventually I came to view the problem as being with down-shifting more than popping out of gear. That's when I began to suspect the gear change quadrant.
When I finally replaced the gear change quadrant in June of 2016, it fixed the problem straight away. The old gear change quadrant hadn't traveled far enough when down-shifting, leaving 1st (and sometimes 2nd and 3rd) gears selected incompletely. The downshift travel of the new unit from Baxter traveled about 3/32" further than the original.
With the new gear change quadrant installed in the outer cover, I fitted a degree wheel to it to observe how far the gear change quadrant deflected from center when the gearshift lever was moved to the up and down-shifting positions. The up and down-shift deflections were nearly identical: 19 degrees for upshift, and 19-1/2 degrees for downshift.
ResourcesFig.9 Gearbox outer cover
Some say an outer gearbox cover gasket can cure certain gearbox problems, but it did nothing for Bonnie. Since fixing Bonnie's gearbox I've used no gasket because she didn't come with one and it's not necessary for sealing - Hylomar or other sealant will take care of that.
ResourcesBritbike.com "Stuck kickstart pin"
Removing the tapered pin holding the kickstart lever in place is not always so easy. The pin gets bent out of shape by the force of repeated kickstarts, effectively jamming itself in the bore. It sometimes helps to jam the kickstart lever forward using a plastic mallet and then whack the pin smartly against the nut threaded flush.
As noted in the Britbike.com thread above, some kickstart pins are made of harder material than others and they tend to distort less than softer ones.
When replacing the tapered pin, be sure to introduce it from the rear with the kickstart lever in the upright position. Installed with the nut at the rear, the pin fouls the footrest.
ResourcesWorkshop Manual (1969 650cc Twins) Section D2: Removing & Replacing the Outer Gearbox Cover Assy
ResourcesWorkshop Manual (1969 650cc Twins) Section D4: Dismantling & Reassembling the Gearchange Mechanism
If the quadrant return springs (57-0404) need replacing, TR7RVMan suggests using T140 springs (57-7051), which are stiffer. They center the gearshift lever better for more positive shifts and ease in finding neutral.
ResourcesWorkshop Manual (1969 650cc Twins) Sections D3: Dismantling & Rassembling the Kickstart Mechanism
ResourcesWorkshop Manual (1969 650cc Twins) Section D2: Removing & Replacing the Outer Gearbox Cover Assy
ResourcesWorkshop Manual (1969 650cc Twins) Section D8: Dismantling the Gearbox
ResourcesWorkshop Manual (1969 650cc Twins) Section D9: Inspection of the Gearbox Components
Although the manual doesn't give any spec, there seems to be a consensus on Britbike.com that layshaft end play should be around .005". By general agreement, it's not critical as long as there is some.
Can't see myself using either of these, but just in case, for future reference: two possible methods to gauge end play.
Be sure to give the gearbox sprocket a good inspection for tooth wear and for 'hooking' of the teeth.
ResourcesWorkshop Manual (1969 650cc Twins) Section D12: Changing the Gearbox Sprocket
Fair amount of trouble to replace the gearbox sprocket, so whenever you are already in the neighborhood it pays to give it a good inspection before putting things back together.
Sprocket wear is contageous, so to speak, as is chain wear. Wear on any one component in the final drive will result in increased wear to the others as well. Giving good care to the drive chain (cleaning, lubricating, and properly adjusting) will give the gearbox sprocket much longer life, thereby postponing its vexatious replacment.
ResourcesWorkshop Manual (1969 650cc Twins) Section D10: Renewing Mainshaft & Layshaft Bearings
ResourcesWorkshop Manual (1969 650cc Twins) Section D10: Renewing Mainshaft & Layshaft Bearings
The gearbox casing holds two bearings:
I've read that these bearings can be difficult to remove, but in 2016 they both came out very easily without even heating the case.
From the primary chaincase side, I used a five-inch long 3/8" drive extension to drive out the layshaft closed end needle roller bearing (57-1606). Access to the bottom portion of this bearing is blocked by the primary chaincase, but I used the extension to tap on the bearing's top, left, and right hand sides. The bearing moved a little with each blow and it took less than a dozen shots before the bearing exited into the gearbox (and across the shop).
The mainshaft high gear bearing (50-0448) is driven out from the inside of the gearbox. I used a 1/2" drive extension and a 1 1/16" deep well socket. Again, the bearing moved easily with each solid blow and it took about ten hits to remove it entirely.
The first two times I replaced gearbox bearings I did it 'Hughie Hancox style': a torch and a hammer with drift. In 2018 this method wasn't working for me at all, and after scrapping the DS needle bearing I enlisted the help of Bob St-Cyr. After watching Bob press them in using a 50-ton industrial hydraulic press I am converted - no more bludgeoning bearings for me!
In order to press in the DS needle bearing I made a wooden base for engine on the primary side: Engine Base
When heating up the gearbox casing I used the non-contact infrared thermometer to take the guesswork out of attaining a 200 degree temperature evenly.
An indispensable trick was to use the old mainshaft as a "stick" to line up the large mainshaft bearing (57-0448) squarely with it's housing in the gearbox casing ( Photo). Once it was started squarely I used a large, heavy drift against the outer race to drive home the bearing ( mainshaft bearing housing and drifts).
Don't forget to fit the circlip.
High gear bearing oil seal, open side to the bearing - tap it all around (like 25-30 times) with a ball peen hammer (beat the sucker in!).
The specially shouldered drift I had made for layshaft needle bearing 57-1606 wasn't exactly right to automatically ensure the bearing's correct protrusion (.073-.078") above the gearbox casing, but I went slowly a little bit at a time and it worked out.
I marked the position of the thrust washer locating peg on the casing with a permanent marker to make it easier to align the matching hole in the thrust washer while installing the mainshaft.
Insure that the bearing lip is below the face of the bronze thrust washer.
ResourcesWorkshop Manual (1969 650cc Twins) Section D11: Reassembling the Gearbox
I've used several methods to assemble and install the gear cluster and in my experience Hughie Hancox's method is hands down the easiest, surest, and fastest way to do the job.
However you assemble, don't forget to seal the shifter fork shaft and the gearbox sprocket if you expect to not have oil leaks. Seal the shifter fork shaft because its drilling goes all the way through the casing. Permatex and Hylomar have both worked well for me. And keep in mind that after the gear box sprocket is installed, the shifter fork shaft drilling cannot be reached.
The layshaft thrust washers are another potential problem area. For starters, don't forget to include them in your assembly. During my first gearbox reassembly I left out the drive side thrust washer and had to take everything out and start over. I know others who have done the same.
The other important thing about the layshaft thrust washers is to be sure they are well installed over their locating pegs and that they don't fall off during assembly. A good smear of heavy grease helps.
During my first gearbox adventure I ended up reinstalling the gear cluster five times, and the transmission twice. The first time I put the cluster in it took just under two hours. The fifth time it took less than three minutes.
In 2015 I tried three different ways to install the gear cluster. I found the WS Manual method (see Method 3, below) of installing the gear cluster as a unit to be the easiest. I made one variation, and that was to index the quadrant and camplate in 1st gear and not in the neutral between 2nd and 3rd as suggested by the WS Manual (see Indexing Camplate & Quadrant below.
In 2016 I used Hughie Hancox's DVD method after making a couple of dry runs and seeing how easy it was. The one deviation I made was that I did not pre-install the mainshaft and kickstarter assy in the inner cover the way Hancox does on the CD. Instead I inserted the mainshaft by itself before putting on the inner cover and then the kickstarter parts.
The next time I'd be inclined to try the pre-assembly method simply to avoid having to torque the kickstarter nut (45lbs) from the right side while trying to hold down the brake on the left side. With pre- assembly, the nut can be torqued (45lbs) while the shaft is held in a vise.
When I re-assembled the gears for the fourth and final time I used the method shown in the WS Manual, i.e. introducing both mainshaft and layshaft with all their parts and the shifting arms as a unit. With enough patience it does work. While the WS Manual shows the mechanic inserting the entire assembly without the rod upon which the shifter arms travel, I achieved assembly with the rod inserted through both shifting arms.
When inserting the cluster, first tip the cluster clockwise a bit to get the roller on the mainshaft gear shifter into the camplate. Then, going in further, tip the cluster counter-clockwise to get the layshaft gear shifter's roller into the camplate. The last time I did it the whole thing took less than three minutes.
Hancox assembles the layshaft, layshaft gears, and mainshaft gears in situ before inserting the mainshaft, already installed in the inner cover, through the mainshaft gears.
As already mentioned, I find this method best of all and I've laid it out, step-by-step, with photo illustrations for those interested.
The thrust washers at either end of the layshaft are held stationary by hardened steel locator pegs in the casing that match holes in the thrust washers. Stuff happens and the pegs get ground down. Here are some descriptions of the problem with details on replacing damaged pegs.
When the Bonnie's locating peg for the DS thrust washer became damaged, I took the engine to Bob St-Cyr and he fabricated a jig which he used to drill anew hole for a replacement peg. Hermit.cc "Locating peg repair"
ResourcesHermit.cc "Camplate & Quadrant Indexing" Three methods, complete descriptions & photo illustrations
Indexing the gearbox camplate and quadrant ensures that when the inner cover is pushed on, the camplate gears and quadrant gears mesh in the correct position relative to each other.
Indexing can be accomplished with the camplate set in any one of three positions: 1st gear, 4th gear, or in neutral between 2nd & 3rd.
For complete details and photo illustrations, click on the "Camplate & Quadrant Indexing" link just above.
Note: On machines with a Norton oil filter head on the downtube, be sure to install the lower forward engine mounting bolt through the back of the inner cover before putting the cover in place. If not, the filter's mounting bracket prevents installation of the bolt from the back, and if the bolt is installed head out, the protruding portion of the bolt on the inside will interfere with the oil lines.
ResourcesTriumphrat.net "T100R gearbox assembly sealant"
I've had good luck sealing inner and outer covers using Hylomar Blue. Hylomar never hardens so it's easy to pull off the covers later. Excess Hylomar also cleans up easily, a rag and friction removes most of it and metal polish takes off whatever residue is left in a jiffy.
ResourcesWorkshop Manual (1969 650cc Twins) Section E1: Removing and Replacing the Fuel Tank
When securing the gas tank, I always begin by tightening the rear mount first. If the front nuts are started first it makes the gas tank lift up in back. I think that's why on so many bikes the threads in the frame for the rear tank mount are stripped. That happened to my brand new 1966 Bonneville, and both of the used Bonnies I've bought came with stripped threads.
Now I use a large tie-wrap over the tank's rear mounting tab (bolt and all rubber parts in place) and through the sidecar mounting hole. Again, I begin with the tie-wrap in back and then proceed to tighten the front mounts.
The front tank mounting stud on Bonnie's timing side came loose once. Leon Goldick of Montreal, who made such a great paint job on Bonnie's tank did the repair and touch-up.
The question often comes up, what to do with the gas tank over the winter season? I confess that I usually get around to draining the tank by February and then leave it empty, but this is not the greatest strategy, especially with ethanol fuel which attracts moisture - the better to rust the inside of the tank. See the link "How to protect the petrol tank" just above for a discussion of what guys do with their tanks in the winter.
After reading all the way through this TriumphRat fuel line thread I've decided to switch from classic look reinforced plastic lines to rubber hose for reasons of safety. The plastic lines frequently leak, and in case of a fire they melt, adding gas to the fuel.
When removing carburettors it is only necessary to disconnect the fuel lines from the gas taps. The carbs can then both be removed as a unit without disturbing the rest of the fuel line connections. Likewise, when tearing down the carbs, one can simply unscrew both banjo bolts and remove them and the fuel lines as a unit.
The brass gas tap fuel line connectors shouldn't be so tight that they can can't be loosened by a few light raps with two or three fingers on a wrench. Avoiding over-tightening prevents the gas tap from turning and possibly breaking the seal to the tank.
ResourcesWorkshop Manual (1969 650cc Twins) Section B7: Concentric Carburettor Type 900 (Illustration)
ResourcesYouTube Raber's Episode #6 Video
The Triumph parts manuals show several different o-ring set-ups for use between the Concentric carb body and the T120R carb adapters. The #6 1968 parts book lists Amal 244/1048, a thick o-ring, used with an insulating block and joint washer. The #7 parts book for 1969 shows the thinner 622/101 (99-0552) o-ring. The parts book for 1970 deletes the insulating block and joint washer and introduces the thicker 70-9711 o-ring.
Although the 70-9711 o-ring doesn't appear in Triumph's parts books until 1970, it was actually introduced sometime in late 1968. My Bonnie, an early 1969 model, was fitted with the 70-9711 thick o-ring, and not the thin 622/101 shown in the 1969 #7 Parts book. The 'Mounting Methods' table (link just above) summarizes the parts book listings for Triumphs between 1954 and 1970.
While the thin Amal o-ring was used most often in conjunction with an insulating block (E2968) and a joint washer (NA43A), the thicker 70-9711l o-ring is used solo, without joint washer or insulating block. The thin o-ring relies on the insulating block to reduce heat transfer between the engine and the carburettor, while the thick ring reduces heat transfer by creating an air gap between the engine and the carb.
In addition to being a more efficient heat insulator, the thicker o-ring reduces the chance of warping the carburettor flanges caused by uneven or over-torquing the carburetter's mounting bolts.
A dab of grease helps keep the o-rings in place while you carefully fit the carburettor to the mounting studs. Next it's finger yoga putting on the rubber insulating rings, cupped washers, and lock nuts, all the while holding the carb ever so slightly off the adapter so the nuts will clear the casting around the ticklers as they are started. Once the self-locking nuts are started, tighten them evenly from side-to-side until there is a .040" to .060" gap between the carb flanges and the adapters.
ResourcesAmal "Parts to Tune Up - Amal Mk1 Carburettor"
The pilot jet (not removable) has a very small diameter and can easily become clogged. Difficulty starting and poor idling can be symptoms of a clogged pilot jet. See " Cleaning Pilot Jet" below.
Standard cutaway is 3. Bigger number=Larger Cutaway=Weaker Mixture.
The needle is notched to be adjustable up and down using a clip. Raising the needle enriches the mixture, lowering it makes it leaner.
Concentric needles are .0985" in diameter, and being made of steel, wear slowly, unlike the jets, which are made of soft brass and wear out more quickly.
The default position for a standard 3-notch needle is the middle notch.
I received needles from MAPCycle that had four notches. During 2016 winter teardown I found the left needle one groove higher than the right side. I set them both to second groove down from the top.
One way to check jet wear is with go and no-go pin gages. The correct gage sizes for a .106" jet would be .1058"(go) & .1062"(no-go).
I've read on BritBike.com that pin gages can be had for about $3 each on Amazon, but I was unable to find the required sizes there. I ended up contacting Vermont Gage directly and they directed me to their online "Distributer Finder". From there I contacted Russell Supply in Burlington, Vermont and they sent me the two pins with a convenient pin holder and all in a very nice secure case for $31 plus shipping. Very pleased with these - they've allowed me to accurately assess the condition of the jets in my collection. Many turned out to be quite worn, but some are still perfectly usable.
See link above to Britbike.com needle jet discussion.
WS Manual specifies size 220 main jets, but Bonnie has 190s installed. I don't run on the main jets so much any more.
|Main jet size||220||190|
|Needle position Up = richer||2||2 (middle)|
|Needle jet size||.106||.106|
|Idle speed adjustment screw||1 1/2 out|
|Idle air adjustment|
Screw out for leaner, in for richer
|2 1/4 - 2 1/2||1 1/4 - 1 1/2|
According to Bill Litant (BritIron mailing list), BSA made modifications to concentrics in mid-1969 to improve low and midrange performance. The correct parts match ups are:
|Needles||Needle Jet||Jet Holder|
|2 9/32" long|
One identifying ring
|11/16" long||3/4" long|
|2 21/32" long
Two identifying rings
I removed the chokes from Bonnie's original Amals and never installed them on the replacement Amals. I plugged the hole on top of the carbs with epoxy and it's held up for all the many years. Amal does make a blanking screw: Amal part number 4/137 (StuartMac).
If a carburettor is flooding frequently or, worst case, overflowing fuel, it is likely due to either the float not rising (float holed and filled with gas or hung up on the float bowl gasket) or the float needle not seating well (needle worn out or dirt lodged beneath it).
Triumphrat.net StuartMac's easy method to pinpoint float bowl problem
Another possibility is that the fuel level is simply adjusted too high. That adjustment can theoretically be made by lowering the float needle seat. Tricky, but here's the Triumph Service Bulletin to guide you:
Triumph Service Bulletin #2/73: "Checking & Adjusting the Amal Concentric Float"
On the other hand, it would be easier to replace plastic bowls with Amal 'stay-up' floats. In addition to being impervious to the effects of ethenol, 'Stay-ups' also have adjustable tangs holding the float needle in place and can be bent up or down.
Fuel leaks from the float bowl are sometimes the result of over-tightening the float bowl screws which causes the bowl to warp. If the leak occurs after changing the gasket, or after the bike has been sitting for a period of time with no fuel in the bowl, the leak may cure itself after the gasket has soaked and swelled up sufficiently to make a good seal. I have also stemmed this kind of leak with some Hylomar smeared on both sides of the gasket.
The official remedy is supposedly to flatten the float bowl by gently rubbing it on a sheet of very fine abrasive paper over a completely flat surface. Be aware, though, that removing an excessive amount of metal will affect the height of the float and float needle.
When refitting cable to air slide, don't try to compress the spring against the carb cover, away from the cable end. Instead, pinch the exposed (slack) wire cable with finger and thumb and push the cable (and spring) towards the bottom of the air slide until the cable pokes through the other side. So, compress the spring against the air slide, not the cover.
When installing the needle jet and it's clip - that's when to scrunch the spring up against the carb cover, gently hanging the bottom end over and outside the carb body while you drop in the needle and clip.
I've been using a guitar string to clear the idle jets, but some say this just pokes the dirt back upstream where gas will eventually wash it back down to the jets. John Healy says to use a#78 drill through the pilot air screw hole to pull the dirt out of the jet and downstream:
"Use a #78 (.016") drill mounted in a piece of hobby brass tubing works the best. If you twirl it between your thumb and fore finger as you offer it, it pulls the swarf downstream of the jet to be washed away by the flow of fuel."
ResourcesWorkshop Manual (1969 650cc Twins) Section B11: Carburetter Adjustments
The Workshop manual explains how to sync carburettors in Section B12: Setting Twin Carbs but forgets to mention final adjustment of cable adjusters.
The entire routine for adjusting low speed mixture, idle, and synchronizing:
It's a good idea to open the twist grip and then let it snap shut once or twice in between checking new synchronization settings for the cables.
See Amal Mk1 tuning links.
See Amal Mk1 tuning links.
The next two sections talk about "8-stroking". If you're not familiar with the term, John Healy describes it well on Britbike.com.
Gavin Eisler offers this sage tuning tip on Britbike.com: "At half throttle, if acceleration could be better, no 8-stroking, clean running but slow to pick up maybe spits back as the throttle is opened, that's lean at the needle jet or needle position, try lifting the needle one notch..."
See Amal Mk1 tuning links.
A plug chop is one way to determine the correct main jet size, but there is an alternative. If engine power is flat above 3/4 throttle in top gear, begin increasing the main jet by two sizes at a time until the engine '8-strokes', then go down two sizes. So, to check if installed main jet is correct size, put in a jet two sizes up. If the engine '8-strokes' above 3/4 throttle, the smaller jet is the correct size.
Amal "How to Trace Faults - Amal Mk1 Carburettor"
Follow these informative trouble-shooting discussion links for better understanding.
ResourcesWorkshop Manual (1969 650cc Twins) Section B6: Removing and Replacing the Air Cleaners
When using paper air filters, both air cleaners can be screwed on/off intact, but when using wire and gauze filters (thicker than the paper ones) the right-hand unit must assembled/disassembled in place due to interference from the foreword edge of the oil tank.
I prefer the wire gauze units because they are reusable.
I used to wash them in kerosene, but more recently I've been washing
them with hot water and dish washing detergent.
I like the idea of using a water-based degreaser and then rinsing in hot water, as suggested by Rod Rocket on Triumphrat.net.
Lube all cables with 10W oil (WS manual calls for the elusive 20W) Taping the spout of an oil squirter can to the cables gives good results.
Bonnie is using standard 43" cables for US bars.
New throttle cables. T.S. cable crosses to D.S. through frame and both cables pass through fork on the D.S.
New throttle cables: installed, they measure 42 3/4" (sleeving), or 45" (cable). These are for the new, low handlebars.
T.S. throttle cable crosses to D.S. through space in frame and then both cables pass to left of steering head and NOT through the hole in the headlamp bracket. Seems to give very good slide response.
Neither carburettor has any nipples between them and the cables at this time - perhaps when the new cables have stretched out.
Throttle cables installed without the former cross-over.
Both carburettors now have two nipples between the cables and the carburettors.
Throttle cables originally "crossed over", i.e. the outboard cable on the twist grip went to the D.S. carburettor.
Use oil and not grease to lubricate the twist grip. Grease is too thick and the throttle will 'hang'.
Currently the clutch cable makes an arc and passes through the space between the gas tank and the gas tank bracket on T.S. and resting just on top of the forward oil line acorn nut.
Formally passed to the left hand side through the triangle in the frame beneath tank to rear of coils
ResourcesFig.33 Speedometer and Tach
ResourcesWorkshop Manual (1969 650cc Twins) Section B42: Removing & Replacing the Tachometer Drive
Parts Reference: #7, Fig.33 Page 73 (link just above).
After removing the gearbox from the crankcase always replace Sealing washer (70-7351, Ref.# 33 - same part used for gas taps) as well as o-rings as required.
See speedometer cable below.
Unscrew tach drive plug and add grease after cleaning out as much old grease as possible. When plug is screwed in, excess grease will be expelled at cable connection to drive unit.
ResourcesWorkshop Manual (1969 650cc Twins) Section A19: Speedometer Cable Lubrication
Formally I lubricated speedo and tach cables with light oil using a rag and avoiding the closest 6-8" to the speedo head.
However, Andy Hansen of Vintage British Cables advised me against using oil and recommends grease instead, because the oil can "corkscrew" its way up the inner cable and into the instrument.
After inspecting a new speedo cable I purchased from Andy I wasn't sure if it was adequately pre-lubricated as I could just barely detect a light coat of grease. I emailed Andy and he replied that his cables are indeed pre-lubricated and ready to install. This set off all kinds of bells and bright lights - I have been over-greasing the cables!
So, apply a very light coat of grease after unscrewing the collet beneath the speedo/tach head and withdrawing the inner cable. When replacing the cable be sure the ends are properly seated at both the speedometer gearbox and speedo head.
ResourcesYoutube.com - Crankbuster's "Smiths Speedo Drive Gearbox". Animated assembly of speedometer gearbox showing its construction. Tip of the hat to "BigSky" on TriumphRat.net.
If you're replacing a speedometer gearbox and find yourself confused about whether to purchase one with a 1.25:1 ratio or a 15:12 ratio, chill out: if you do the math you'll realize that those ratios are both the same.
Using a grease gun with the appropriate fitting, periodically add grease to the gearbox.
Replaced Taiwanese Smith pattern with another Taiwanese Smith Pattern from MAPCycle 2014 when putting rebuilt speedo into service. Have original Smith gearbox on hand.
ResourcesBritBike.com - Don's informative post on trouble-shooting & fixing speedometer cable problems
One problem common to Smith's speedometers is a wavering or bouncing needle. This is often caused by poor cable routing, too much or too little lubrication, or too heavy a lubricant (see cable lubrication, above). Another problem can be an incorrect inner cable length (too short or too long).
If the speedo is inoperative, using an electric drill (very low speed only!) to drive the cable or the speedometer head can sometimes help isolate the problem.
Another common problem with Smith's speedometers is resetting the trip meter. Often the trip meter reset handle is difficult to operate. I've found that rolling the bike forward sometimes helps, as can turning the handle backwards (counterclockwise) just a bit before turning forward again. If it still won't turn I go down the road a little ways and try again - usually works. Some say that removing the handle and spraying in a little lubricant fixes the problem, but I'd be cautious of getting lube where it doesn't belong and creating problems (see Cable Lubrication just above).
ResourcesWorkshop Manual (1969 650cc Twins) Section G1: Removing the Telescopic Fork Unit (Covers Handlebars)
Late '60s Triumph handlebars are 7/8" in diameter. I've tried three styles of handlebars on my Bonnie:
Esthetically, I like the Commando bars the best. For a complete, photo-illustrated run-down of British motorcycle handlebars complete with dimensions, see the BritishCycle.com link just above.
For the handlebar shock-absorbing mounting to work properly, the parts must be installed in the correct order and with the hemispherical washers in the correct orientation, i.e. the hemispherical sides facing each other.
It is also important that the hemispherical washers have indents around their inner hole. The indents match the shoulders on the shanks of the eye bolts and if they are not present the eye bolts can be stressed to the point of breaking. (John Healy).
The correct order of the parts is listed below and shown in the figure to the right.
Safety Note: If the eyebolt makes contact with the head lug it can create a safety issue, see Triumph Service Bulletin #306 in following link:
ResourcesTriumph Service Bulletin #306: flexible handlebar mounting "Flexible Handlebar Mountings on 650s".
Use similar method to install new bushings.
One suggestion that surfaces on forums to keep handlebar grips in place is hair spray. I tried it once and quickly learned how dangerous it is. Hair spray works ok as long as things are dry, but the moment there's moisture it becomes super-slippery - so slippery that light pressure from two fingers will slide a grip right off the bars.
The old school method was friction tape - not plastic electricians' tape, but cloth friction tape. Wrap the tape on the bars and then smack the grip over the tape.
Perhaps a good solution is Three Bond Griplock #1501C. Pricey, but have you ever had your handgrips slide right off the handlebars while tooling down the road in a little rain shower?
ResourcesWorkshop Manual (1969 650cc Twins) Section E5: Adjusting Rear Suspension
Dealing with the split ring clips at the top is much easier with two sets of hands.
When replacing the shock absorbers, don't force the mounting bushings into place from the rear of the frame bracket or from directly beneath the mounting holes for the shocks. Instead, insert the bushings from beneath the spare hole in frame bracket and then slide them to the rear and into place. May need a few little plastic mallet taps, but you should not have to beat on them if you take the right approach.
Outside to inside, #7 shows bolt, plain flat washer, spring lock washer, plain nut.
Replaced with new units in 2013.
Ok for bushings to be pushed off-center apparently.
#7 shows only one shock absorber bolt, and it appears head out. On the brake side, however, I've put the nut on the outside on the bottom so the bolt doesn't scrape on the brake drum cover.
ResourcesWorkshop Manual (1969 650cc Twins) Section A16: Telescopic Forks Lubrication
Triumph 650s used three different width axles:
The following table is for unit 650s:
|Unit, before 1969||Unit, 1969 and later|
|Fork Legs Center to Center||6-1/2"||6-3/4"|
|Axle Brake Plate Thread||20 tpi 3/4" BSC||20 tpi 3/4" UNEF (Extra Fine)|
1-1/16" AF a fair fit
or 5/8" BS
The gaiters can be removed and replaced by removing the front wheel and fender. When installing new gaiters this way the 'sticking point' can be getting the tops of the gaiters past the dust excluder sleeve nuts. A method that works well is to dig the tips of both thumbs right into the gaiter just below the "collar" at the top and push them right on.
ResourcesWorkshop Manual (1969 650cc Twins) Section G1: Removing the Telescopic Fork Unit
Remove as a unit to maintain steering head bearings.
Remove separately to maintain fork - oil seals, etc.
ResourcesWorkshop Manual (1969 650cc Twins) Section G2: Dismantling the Telescopic Fork
ResourcesWorkshop Manual (1969 650cc Twins) Section G3: Renewing the Front Fork Seals
I have replaced Bonnie's fork seals: May 2014/March 2007/May 2003.
ResourcesWorkshop Manual (1969 650cc Twins) Section G6: Reassebling and Refitting the Telescopic Fork Unit
With front fork removed as a unit.
ResourcesWorkshop Manual (1969 650cc Twins) Section G7: Telescopic Fork Alignment
When replacing front wheel and axle, the front fork should be aligned as follows.
ResourcesWorkshop Manual (1969 650cc Twins) Section A14: Greasing the Steering Head Ball Races
(For refitting with fork, see Refitting Fork to Frame just above)
ResourcesFig.18 Steering Damper
In 1969, only the TR6C came equipped with a steering damper. I found the dampers on my '66 Bonnevilles to be both useful and aesthetic so I retro-fitted one on Bonnie. Very good on bad roads and windy days, just be sure to loosen it when you get into town!
My theory is that wind affects a down-road trajectory not so much by its action on the bike, but on the upper body of the rider. The wind pushes the rider, whose shoulders move, and the motion is transmitted to the handlebars. The steering damper virtually eliminates the effect.
When I retro-fitted a damper to Bonnie I neglected to fit 'locating pin' 97-2107, which, I learned recently from TriumphDave's Britbike.com post, prevents the sleeve nut from being loosened so far that it falls off. Hats off to Dave, I'll soon have one on order.
The steering lock cylinder is held in place by a counter-sunk set-screw. The set-screw hole is covered over by a plug which must be dug out before removing the set-screw and lock cylinder.
All Front & Rear Axle Retainers, Support Rings, and Dust Covers Illustrated
This photo shows the top and bottom sides of all grease retainers, dust covers, support rings, backing rings, and retaining rings on the front and rear wheel axles. It also includes dimensions, part numbers, and reference numbers.
Front Axle bearings, covers, rings, and retainers
This photo shows the orientation of all parts on the front axle, including the dust cover, retaining ring, support ring, grease retainer, bearings, and circlip.
Rear Axle bearings, grease retainers, and retaining and backing rings illustrated
This photo shows the assembly order of the rear axle bearings, grease retainers, retaining ring, backing ring, and speedometer gearbox.
Rear Axle nuts and distance pieces
A photo showing the assembly order of the rear axle inner and outer nuts and distance pieces.
ResourcesWorkshop Manual (1969 650cc Twins) Section F: Wheels, Brakes, and Tires Table of Contents
ResourcesWorkshop Manual (1969 650cc Twins) Section F1: Removing & Refitting Front Wheel
ResourcesWorkshop Manual (1969 650cc Twins) Section F8: Removing & Refitting Wheel Bearings
[Replaced Bonnie's FWB May 2014 @60kmi (MAPCycle sealed bearings) & July 2007 @36kmi]
I disassembled the wheel and re-packed the bearings after cleaning them out with kerosene and compressed air.
The (cupped) grease retainer on the inside of the left-hand side was in backwards I think - the cavity was facing away from the bearing so I put both the retainers back with their cavities facing the bearing the way it appears to be in the parts manual.
ResourcesWorkshop Manual (1969 650cc Twins) Section F5: Brake Adjustments
When reassembling the brake, note that:
From the WS Manual evidently:
But as always, there's more to it than that.Triumphrat.net Rancidpegwoman, the Village Idiot, and others divulge their best brake tuning secrets
ResourcesTriumphrat.net StuartMacs tips on fitting the front fender stays to fork
The front wheel and tire can be removed without disturbing the fender and fender braces if the tire is deflated somewhat
The front fender brackets (Ref.5 in Fig.26 Fenders ) fit on the lower fork legs pointing forward with the bottom angle projecting upwards.
The bolts (Ref.23) which fix the stays to the brackets face nuts out (Ref.24).
Figure 26 (#7) doesn't show how the forward and center stays (Ref.2 and Ref.3) fit onto the fender brackets (Ref.5). They should both be fixed to the outside of the fender brackets as shown here.
If the fixing bolts are hard to get through the stays and bracket, slacken the bolts holding the stays to the fender and then give the bolts a rap with the plastic mallet.
[The mounting hole for the bottom stay (Ref.4) in Bonnie's used replacement lower fork leg is threaded, so the bolt must be threaded in and out.]
ResourcesWorkshop Manual (1969 650cc Twins) Section F: Wheels, Brakes, and Tires Table of Contents
ResourcesWorkshop Manual (1969 650cc Twins) Section F2: Removing & Refitting Rear Wheel
Note that the back end of the bike must be slightly elevated (chain hoist or bike jack) in order to create sufficient clearance between the rear tire and the fender for removal.
Install the chain guard first (loosely) and then install the wheel.
Putting self-locking nut (14-0702) on bolt (14-0113) fastening the front of the chain guard to the frame can be a huge pain. Try this:
The bolt head is pretty well held in place by the fender for this operation, it only needs held with a wrench for the final tightening, at which time it is more easily accessed when the side panel is removed.
Alternatively, jam small metal chisel between fender and frame mount to make room for nut, held in place with fingers while threading on nut as above.
Note: installing this bolt and nut has been easier the last few times - perhaps because the stainless fender has become more 'relaxed'.
When re-installing the rear wheel, before tightening the inner axle nuts the speedometer gearbox must be aligned to allow the speedometer cable to follow beneath the swing arm. Doing this with the wheel mounted on the bike requires the service of a very thin, 1-5/16" wrench. Without such a wrench, I align the speedo gearbox, center the brake shoes (see below), and tighten the inner nuts before installing the wheel on the bike. Getting the correct speedo gearbox position is pretty much trial-and-error.
The rear wheel brake shoes should be centered to the axle to prevent the brakes from 'pulsing'. To center the brake shoes, apply the brakes while tightening the inner axle nuts.
The inner axle nuts can be tightened with the wheel in place but it requires a very thin 3/4" wrench. Since I don't have such a wrench, I center the brake shoes and tighten the nuts on the workbench this way:
In the beginning I tended to overtighten the inner nut, sometimes making the wheel turn stiffly. Ok if it eases up with a few rotations, but excessive binding can damage the wheel bearings. In case of the wheel binding before the speedo gearbox is clamped sufficiently, add a shim to the spacers to increase clearance.
I finally acquired a thin 1-5/16" wrench, making it possible to do the entire procedure with the rear wheel on the bike. So easy using the brake pedal to apply the brakes. And, with everything in place and held securely, you can align the speedo gearbox perfectly every time.
I consider a thin 1-5/16" wrench a must-have tool for any Triumph shed.
Brake torque stay (ref 11 page 37) should go on before the plate for passenger foot peg and muffler bracket.
Both ends of torque stay are supposed to use the same nuts (14-0304)(3/8W) and spring washers (PCW73A), but on Bonnie one is thicker front) and one is thinner (rear).
The "C"-clamp on the torque stay adjusts the bottom of the chainguard with respect to the tire and the chain. It must be fit so that it rests ON TOP of the chainguard bracket to allow for adjustment. Bit of a PITA, but fitting the nut and bolt with the passenger peg and mounting plate removed is much easier.
ResourcesWorkshop Manual (1969 650cc Twins) Section F8: Removing & Refitting Wheel Bearings
Replaced Bonnie's with sealed bearings from MAPCycle May 2014 60,000mi.
ResourcesWorkshop Manual (1969 650cc Twins) Section F5: Brake Adjustments
Shouldered end of the rear wheel spindle goes to T.S. Seerear axle photo and illustration.
If removing the brake cam lever ( Ref 32 Figure 20) from the brake cam post is difficult, try this:
When reassembling the brake, note that:
Over time, a Triumph rear brake pedal pivot becomes a loose fit. This would be an easy fix if Triumph had used a bushing there, but they didn't. Here's how one Triumphrat.net listee fixed the problem:
TriumphRat.net WOL: Sloppy Brake Pedal
With everything assembled, it's nearly impossible to splay the cotter pin that fastens the rear brake rod to the brake pedal lever: therefore, do it at one of these stages of disassembly:
ResourcesWorkshop Manual (1969 650cc Twins) Section E4: Removing & Replacing Rear Mudguard
Bracket fits inside the rear frame loop. See TBA photo.
Rear fender bracket on frame 1/2" bolts (same bolt used for oil bottle bracket).
Note that the two rear fender bracket mounting bolts (14-0113) (Ref 32 Figure 26) must be installed before putting on the fender.
ResourcesWorkshop Manual (1969 650cc Twins) Section C11: Rear Chain Alterations & Repairs
When lubricating or working on the chain, use a short piece of rain gutter to contain the chain and the mess.
If the chain happens to fall off the rear sprocket, it can be replaced by inserting the tapered end of a chopstick through the spokes and into the hole at the end of the chain and using it to drag the chain far enough back to engage the sprocket and be pulled around using the wheel.
Replacing a master link on the side away from you is awkward. Instead, insert a spare master link from your side of the wheel - it keeps the ends aligned perfectly and gives tactile reference for installing the actual master link from the opposite side.
The orientation of the master link clip is critical - the closed end of the clip must always be at the front as it travels around in the direction the chain is moving. You can think of the clip as a spawning fish that's swimming up the back of the rear sprocket - but with the flow, not against it.
ResourcesDirtTricks.com ""Measuring Chain Wear", Greg Burns
As Burns points out in his article "Measuring Chain Wear", chains do not stretch, they become longer due to the pins wearing an oblong pattern in the bushes.
When wear progresses to the point the chain is no longer a perfect match with sprocket teeth, wear to both sprockets quickly accelerates.
The workshop manual describes a standard method for checking wear:
How much wear is acceptable? Opinions differ. Extrapolating from 20 links to 100, the manual sets out 1.25" (1-1/4) as the maximum acceptable increase in length over 100 links.
However, Burns claims that "Most chain manufacturers limit chain wear to approximately .006" per link". That works out to .6" max wear per 100 links, or just under half what the manual considers maximum acceptable wear.
Which is right? I incline toward the figure suggested by Burns for the simple reason that a new chain costs less than a new chain and two new sprockets. And a lot less trouble to change!
For asphalt riding I clean and lubricate the chain at each oil change, or every 1,000 miles for Bonnie. When I'm mostly riding the gravel I clean the chain every 500 miles.
Kerosene used in chain cleaning can be reused many times. Simply allow the suspended particles to settle and then gently pour off the clear kerosene into a clean container, ready for the next cleaning.
In an old pan, immerse the clean chain in heavy (summer) chain saw bar oil for a couple of hours. Next, hang the chain to drain excess oil. Finally, wipe the chain lightly with a clean rag before reinstalling it.
Pull the clean chain back on with the old chain.On the bike, after a ride
Always lube a mounted chain when it's warm after a ride! Putting oil on a cold chain will just make a mess on the floor. Applied to a warm chain, oil will penetrate inside the rollers where it's needed instead of dripping off.
Using the tapered tip of a gear oil container, I apply heavy chainsaw bar oil to the chain while I spin the rear wheel rapidly. It's surprising how much oil can be applied to a warm chain without it dripping off, but if done regularly it really doesn't take that much - less than 2 ounces (quarter of a cup). If oil drips off a warm chain, that's too much.
Do not over-lube! An excess of oil can seep into the rear wheel brake drum and spoil the brake shoes.
With the bike on the center stand, check rear chain slack half-way between front and rear sprockets on the lower run. With the chain in its slackest position, use a finger to push it up and then down. The distance between those two points is the chain slack and should normally be 1-3/4".
When properly adjusted (1-3/4" slack on center stand), the chain will look to be too slack, but when a rider compresses the rear springs the swing arm raises, tightening the chain.
To learn a cool way to find the slackest place in the chain (hint: a little dab'll do ya!), and a way to get an accurate measurement of the slack, click this link (eye-roll) to TR7RVMan's complete description of rear chain adjustment on BritBike.com. As always, Don has the good stuff!
ResourcesWorkshop Manual (1969 650cc Twins) Section F11: Removing & Repairing Tires
The 1969 Triumph Workshop Manual gives an incorrect tire pressure for today's tires.
Although the General Data section of the Triumph Workshop Manual for 1969 Unit Construction 650 Twins states a tire pressure of 24 lbs for front and rear, it must be understood that the modern versions of even vintage tires are made with far superior materials and technology than the originals, and they are not only capable of higher inflation pressures, they require them.
The first few years I had Bonnie I used the WS manual's recommendation of 24/24. Eventually I took notice of the weird wear pattern on my front tires: they were cupping badly. The tire guy said raise the air pressure so I did, to 30/30. End of cupping problem.
Dunlop K-70, 3.25 x 19
Dunlop K-70, 4.00 x 18
Put valve stem to yellow dot.
ResourcesWorkshop Manual (1969 650cc Twins) Section E: Frame and Attachments Table of Contents
ResourcesWorkshop Manual (1969 650cc Twins) Section E8: Removing and Replacing the Swinging Fork
In 1966, Triumph moved the speedometer drive from the gearbox to the rear wheel axle. To accomplish this they had to widen the axle end of the swinging arm frame by 1/4". So be aware that earlier swinging arm frames are incompativle with those of the 1966-1970 unit 650s.
When replacing the swinging arm, the large 15/16" nut (Ref 10) and tab washer (Ref 9) go on the DS, and the 7/8" bolt (Ref 8) head goes on the TS.
Was getting a bit of back-and-forth play (grab two loose ends and try to rotate swinging arm left or right) so I replaced the pivot bushes (ref 2) in 2014 (53,010 miles).
Don't be tempted to put the shocks on before the swinging arm because they'll just be in the way.
Like the first time, I had difficulties getting the bolt to thread into the frame on the drive side. But now I know the trick - after trying to push the swing arm this way and that way in an effort to get the threads to take I finally got the idea to use the impact screwdriver with a 9/16 BS or 7/8" socket. Tapped the driver with my plastic mallet while turning slowly and the bolt went right in no sweat!
Assembled 2 sleeve bushes (5/36) and spacer (6/36) with flanged washers and new o-rings, packing with grease as they went
Inserted the bolt, using a small diameter dowel to help line up the spacer and bushes.
Put the nut on loosely and used grease gun to fill until grease bled out both ends. Note\; I wouldn't put much pressure behind the grease because excess will have to be squeezed out the holes when the swing arm is inserted into the frame brackets.
Used plastic mallet (lightly) to position the arm and inserted the bolt. Likewise, played with other end a bit with the mallet and the bolt threaded into the frame bracket on the primary side.
I initially torqued the bolt (8/36) - 7/8" socket - to 50 pounds (the new torque wrench is fun!) but the swing arm was binding slightly so I backed off a tiny bit until it was free.
Use 15/16" socket for the nut (10/36).
ResourcesFig.12 Side stand
Easier to remove with stand folded against frame. Use 3/4" wrench to remove nut (faces out) and then give the bolt a rap to loosen up and start on its way out. Then open the stand and wiggle while pulling on the bolt. Slip the spring off after the bolt is removed.
Nut is up and out or it will be in the way of the spring.
Easiest way to get it on is to put the spring in place on the frame and the sidestand and then pull the sidestand into place.
ResourcesFig.12 Center stand
Ever arm-wrestle a center stand spring? They're small but mighty! Many swear words have been uttered during center stand spring installations, but happily, there are techniques which can reduce, and possibly even eliminate the amount of brute strength required.
The easiest moment to install a center spring is before putting the stand on the frame and before putting the engine in the frame. Simply flip the frame upside-down and hold it down with your feet, using a towel to protect that new powdercoat of course. Then, hold the loose stand close enough to the frame to slip both ends of the spring into place, and then holding the stand by the legs, pull it into position and slip the bolts in. Easy-peasy! Note this technique relies on pulling instead of pushing.
The job becomes more difficult when the engine and center stand are installed in the frame, but see "Install Center Stand Spring Using String"
ResourcesFig.29 Passenger Footrest
Remove left-hand bracket to make it easier to access the bolt holding the chainguard "C" clamp to the torque stay.
Brackets need to be slack to insert bolt for rear footpegs from behind - best to pre-assemble.
ResourcesWorkshop Manual (1969 650cc Twins) Section E10: Removing & Replacing the Rear Frame
The 23/34 bolt on the bottom is 5/8" used 1/2" socket.
The 21/34 bolt head is also 5/8", but its 21/34 nut is 11/16", spanner for the former and 1/2"socket for the latter.
Bonnie's frame and tinware have been powder coated, as well as the following parts:
Not powder coated:
ResourcesFig.24 Battery Carrier
ResourcesWorkshop Manual (1969 650cc Twins) Section E3: Removing & Replacing the Battery Carrier
There may be better ones, but this order of assembly works ok
Regarding the next 4 steps: it's much easier to put the rubber spigots (82-6673) inside the battery holder straps and then push them onto the frame lugs then it is to put the spigots on the lugs and push the carrier straps over them.
See also: Oil Tank
ResourcesWorkshop Manual (1969 650cc Twins) Section E14: Fitting Replacement Seat Covers
To remove seat, first remove left side panel, then remove bolts for just one seat hinge and slip the other one off.
Installing seat latch: push latch part way through it's frame, insert spring and washer, then the rest of the way through. Keep spring and washer in place with right-angle pick while inserting cotter pin.
ResourcesWorkshop Manual (1969 650cc Twins) Section H: Electrical System Table of Contents
ResourcesWorkshop Manual (1969 650cc Twins) Section H2: Trouble-Shooting the Ignition System
If your bike is blowing fuses, this trouble-shooting tip from John Healy will be a great help in tracking down the short: replace the fuse with a 12v light bulb and then begin disconnecting circuits one at a time. When the light goes out you're found the circuit which is shorted. Start looking for faults such as worn insulation or loose bare wires.
ResourcesWorkshop Manual (1969 650cc Twins) Section H20: Wiring Diagrams
ResourcesWorkshop Manual (1969 650cc Twins) Section H1: Battery Inspection & Maintenance
Replacement battery should be a sealed, maintenance-free unit with a minimum 9Ah rating.
For battery carrier dimensions, see Battery Carrier just below.
|Koyo YTX-12-BS||5-1/8"||5-7/8"||3-5/16"||5 stars, but hard to find|
|Motobat AGM MB9U||5.3" (13.6cm)||5.2" (13.3cm)||3" (7.6cm)||12v/11aH Popular for British bikes|
|PowerStar PM9A-BS AGM||5-1/2"||5-1/4"||3.0"||12v/9aH|
|PowerStar AGM PS-12-BS||5-1/8"||5-7/8"||3-3/8"|
|Yasua||5-1/8"||5-7/8"||3-3/8"||(Bonnie - June 2018)|
ResourcesWorkshop Manual (1969 650cc Twins) Section H12: Fuses
Use 35 amp British fuse, or 15-17.5 amp US fuse (continuous slow-blow).
When I fabricated my own wiring harness I fused both the positive and negative battery terminals.
Fusing both battery leads is effectively like having a spare fuse at all times because the positive battery lead can simply be shorted to ground without a fuse.
Once on a trip in the Green Mountains I turned on the ignition switch while coasting down a steep hill in fourth gear. Bang! A big pop and the negative lead fuse blew. No spare fuses with me - I'd left them on the workbench! I shorted together the positive fuse's carrier leads and put the good fuse in the negative lead.
Battery carrier inside dimensions: H x W x D.
For more info, jump to Battery Carrier section.
ResourcesWorkshop Manual (1969 650cc Twins) Section H4: Charging System
If stator holes won't line up with the stator studs in the crankcase, or the rotor is off-center in the stator, do not be tempted to adjust the alignment by hammering on the studs. Doing so risks cracking the crankcase. Do any bending with the studs removed and held in a bench vise. (See stator link above).
ResourcesTriumph Service Bulletin "Loose rotor center or rotor retaining nut"
The way the Lucas rotor is constructed, it's possible for the rotor center to become loose from the outer part holding the magnets. This can be checked by tightening the rotor in place with the stator removed. Gripping the rotor with both hands, turn over the engine in both directions and feel whether there is any slipping movement. Rotors that have become loose cannot be repaired ordinarily, they must be replaced.
See note above on Tightening Rotor Nut.
When reinstalling the rotor, important to be sure there is sufficient clearance (.008"-.012") all the way around between it and the stator.
Here's a method often cited at the Britbike Forum:
With engine running and lights on, blip the throttle. If intensity of headlight does not increase with revs there is a problem somewhere in the charging system. This can also be verified by connecting a voltmeter across the battery terminals to see if voltage rises when revs do.
The alternator can be checked by connecting either a voltmeter (AC) or a 12 volt bulb across the alternator's disconnected leads and kicking over the engine.
ResourcesHermit.cc Original Wiring Harness - 2005
The selenium rectifier and grounding straps have already been disconnected.
(See original and repro photo sets above)
Beneath gas tank. Tied about an inch to the rear from the "Y" (along with clutch cable) to upper tube through space in frame forward of the coils. Then tied again to upper tube just forward of the rear gas tank mount. Passes over the top of the rear loop into the battery area. (Photo)
Passes through the stanchions from the rear (Photo)
2006: Eliminated horn and integrated dip switch wiring into the Lucas lighting switch in the headlight shell (see wiring diagram above)
2006: Tied just above bottom side cover mounting stud and then falls to follows the frame member before looping to the switch.
ResourcesBritbike.com Bullet connectors, crimp or solder? High caliber posts, no hollow points.
Bullet connectors are compact, simple, and generally quite reliable. They sometimes get a bad rap for poor connections due to corrosion, but that issue is likely encountered primarily in very humid climates or coastal areas with salty air.
I recently learned that new bullets on the market are sized for metric wire and not the larger Imperial-sized wire found in original British motorcycle wiring harnesses. Accordingly, a modern bullet will not crimp tightly enough to original wiring, even if it's made for the appropriate number of wire strands. Inserting short wire 'shims' to pad out the larger size of the bullets might be a viable work-around.
Some bullets have two crimping points, one for the wires and one for the insulation. The wire crimp makes the electrical connection and the insulation crimp provides strain relief. Bullets available for British bikes today generally have a crimping point only for the wire.
There's some debate over whether it's best to crimp or solder bullets. Crimping provides a good mechanical attachment, and soldering insures good conduction, so to me it's logical to do both. There is, however, one caveat.
Unless done with care, soldering can actually reduce reliability.
Consider this: when solder flows over the individual wire strands they become bonded solid. Lacking flexibility, a solid wire segment is way more prone to vibration stress and eventual breakage. This can be avoided by using only the smallest amount of solder at the tip of the bullet and allowing it to flow only as far as the mechanical crimp, thus preserving the vibration-absorption properties of the strands where they enter the bullet.
To keep the bullets from falling off the wire while you crimp/solder, strip the wire a wee bit long and splay the protruding ends slightly after inserting the wire into the bullet.
If you do solder, remember to remove all remnants of flux using warm water and a rag. We don't want any corrosion now, do we?
If you have the nervous system of a squirrel you might succeed in using a dual-range soldering gun's low setting for soldering bullets, but something like a 35-watt pencil gives more control over the process. Either way, be sure to clean the soldering tip for efficient heat transfer and avoid 'cold' solder joints by heating the bullet sufficiently and flowing the solder to it and not the pencil or iron.
ResourcesWorkshop Manual (1969 650cc Twins) Section H17: Twintone Horns & Relay
ResourcesWorkshop Manual (1969 650cc Twins) Section H9: Headlamp
Photo showing Bonnie's headlight shell wiring:
The headlight reflector unit (99-0686, or LUCAS 516798) is held in the headlight rim (99-0692, or LUCAS 553248) using fixing wires (99-683, or LUCAS 504665).YouTube.com Classic British Spares: "Installing & Removing Lucas Headlight Wire Clips"
ResourcesTriumphRat.net Head/Tail/Brake Light LED Replacements
ResourcesWorkshop Manual (1969 650cc Twins) Section H11: Tail & Stoplamp Unit
ResourcesWorkshop Manual (1969 650cc Twins) Section H15: Warning Lamps
I've replaced this switch three times on Bonnie. After installing new repro switches I've attempted to recondition the old ones by taking them apart and re-assembling. Never had any success, maybe you're more lucky than me.
The figure below shows the internal connections of the Lucas 35710 (99-0563) light switch in all three positions. See also this
chart-style pin-out for the 35710.
ResourcesWorkshop Manual (1969 650cc Twins) Section H13: Ignition Switch
Repro editions of the Triumph ignition switch are notoriously prone to failure and the slightest weight of a key fob attached to the key is known to exacerbate the problem - leave your ignition key naked!
An intermittent ignition issue is frequently due to a defective ignition switch. If you're having an ignition problem, one of the first things to do is install a jumper lead from the battery to the coils, thus by-passing the ignition switch.
ResourcesWorkshop Manual (1969 650cc Twins) Section H5: Zenner Diode Charge Control & Testing
On Bonnie I replaced the selenium rectifier and zenner diode with a Podtronics Rectifier/Voltage Regulator in 2015
Condensers eliminated by Pazon in 2014 (left wiring in place and all original condenser parts, brackets, covers, etc. are retained in inventory.
Had previously (2006, new harness) fabricated a custom bracket and moved condensers from original location to beneath gas tank. See photo below.
Often suspected that Bonnie's habit of firing on only one cylinder after encounters with water (car washes, rain storms) might originate here. Especially when the problem persisted after waterproofing the ignition wires' passageway through the timing case to the points.
ResourcesWorkshop Manual (1969 650cc Twins) Section H2: Coil Ignition System
On a bike with a points ignition setup it is normal, but not desirable, for one or the other coil to heat up if the ignition switch is left on. This is due to current from the battery energizing the coil through the closed set of points.
If you need to work on the electrical system with the battery connected and the ignition switch in the on position, remove the points cover and slip a piece of paper or plastic between the contacts of the closed points.
EI (electronic ignition) units are programmed to automatically open the coil circuits after a set amount of time if the ignition switch is left on.
Note that the head steadies must be installed before installing the ignition coils.
Note that just because correct resistance readings are obtained for a coil does not mean that the coil is good. It may be arcing internally or its readings may change when the coil becomes warm.
Resistance readings for 6v coils:
Resistance readings for 12v coils:
Left Coil (DS)
Right Coil (TS)
2017: Replaced 6v TriCor coils with 6v Taiwanese units (76,000mi).
2014: Replaced 12v German ignition coils with 6v TriCor 'High Spark' coils during changeover to Pazon CDI.
20??: Replaced 12v Lucas coils with 12v German units during changeover to Pazon CDI.
(12v originals & German coils are in inventory, along with one good 6v TriCor.
ResourcesWorkshop Manual (1969 650cc Twins) Section H19: Capacitor Ignition
Pazon PDF Installation, timing, and trouble-shooting
"This will tell you if the box or the sensor is the problem."
ResourcesVintageBikeMagazine.com "How to Trouble-shoot a Boyer Ignition" Includes good info relating to all EI systems
ResourcesPodtronics: Instructions & Diagram
First run (2 miles - Chemin Vallieres)
Second run (5 miles - Ayers Cliff)
Third run (28 miles - Tyson's Corner)
Fourth run (50 miles - Sherbrooke)
Fifth run (50 miles - Katevale,Magog,Gendron,GVille,Brown's Hill, Ayers Cliff)
High revving problem was due to such poor condition of o-ring for idle adjustment that the idle screw had no friction and just kept screwing itself in (higher revs) each time i adjusted it. A new o-ring fixed the problem right up.
Although cable friction was not to blame for high-revving, i nevertheless decided to eliminate the cable tie I'd put around upper member beneath gas tank to hold throttle cables as well as clutch cable tight to the frame. Without the tie they take a larger radius arc and seem more "relaxed".
Severe miss and dead battery due to
I corrected above and timed the engine first using Hancox's static method and then using the strobe. Running really well!
"The Bonnie Ref" is an outgrowth of my efforts to maintain and repair "Bonnie", my 1969 T120R Triumph 650 Bonneville. From the very beginning I have been the beneficiary of much help and information from fellow CVMG club members, the BritIron mailing list, and classic Triumph forums such as Britbike.com and Triumphrat.net.
To organize the information and make it accessible, I used HTML and lots of hyperlinks. Tired of the dark, blurry photos in workshop and repair manuals, I included my own digital photos and illustrations created in Fireworks 2.0 (I own it, it's mine - screw Adobe!). Eventually I began linking to useful information from around the Internet.
I am not a mechanic or expert by any means, but I hope you'll agree that this "manual" provides quick and easy access to volumes of interesting and useful information on the late 60's Triumph 650 motorcycles. Enjoy!
Corrections, suggestions, or comments welcome: tmc at hermit.cc.
Cheers! and Happy Trails
Bruce Miller (The Hermit)
1969 Triumph Bonneville T120R
The Triumph Meriden factory began production for new model years in August of the prior year. In October 1968, during the 1969 model year, Triumph changed to a new serial number system. The new serial numbers used two letters to designate the month and year of production, and a 5-digit serial number, beginning at either 00100 or 00101, depending upon what source you read. So, in October of 1968, Bonnie was either the 24th or 25th Triumph twin to use the new serial number system.
I purchased Bonnie from Frank Holmes at Frank's Brit-Barn in New Hampshire on June 28, 2003. There were just over 14,000 miles on the clock. She came in very original condition and complete except for Windtone horns.
I re-styled Bonnie to look more like the 1966 models I had 'back in the day'. Things like fitting '66 retro tank badges, stainless steel fenders, and steering damper, moving the zenner diode from the headlight back to the side panel, and dispensing with the exhaust pipe balance tube. All of the original parts - tank badges, fenders, seat, exhaust & mufflers, handlebars, carburetors, points, and many others, I've kept, so possible to restore to near-original condition.
A Hyperlink Junkie's Illustrated Field Guide
to the 1969 Triumph Bonneville
adjust primary chain tension
adjust valve rocker clearance
air cleaners, installing
air screw o-ring
air slide (carb)
align rear wheel
alpha-numeric part# conversion
Amal parts, '69 650s
annealing head gasket
axle retainers, rings, and dust covers
axle parts, front illustrated
axle parts, rear illustrated
Banjo bolts, orientation
battery carrier, dimensions
battery carrier, reassembling
battery specs & replacements
Boyer Ignition trouble-shooting
brake light, switch
brake light, switch harness routing
brake, front - adjusting
brake, front - centering shoes
brake, front - reassembly
brake, front - removing
brake, front - replacing
brake pedal, D.S. engine mount, torque stay
brake pedal wear
brake, rear - centering shoes
brake, rear - disassembly
brake, rear - reassembly
brake shoe illustrations
brake torque stay
British motorcycle forums
British standard threads
cable, speedometer - lubrication
cable, tach - lubrication
camshaft bushes, renewing
camplate positions (gearbox)
carburettor cables,air slide,spring
carburettor, cleaning idle jet
carburettor, concentric cross-section
carburettor, jet/needle/cut away
carburettor, leaking float bowl
carburettor, mid '69 BSA modification
carburettors, specs & settings
carburettors, removing as a unit
Amal tuning links
low speed & sync
center stand spring
center stands/mounting hardware
chain, see Primary Chain
chain, see Rear Chain
clutch assembly, removing
clutch assembly, replacing
clutch center/thrust washer compatibility
clutch drag, causes of
clutch operating mechanism "pops"
clutch pack thickness, Trumph & Aerco
clutch pressure plate adjustment
clutch lever pull too heavy
clutch rod adjustment
coils - see ignition coils
color code, wiring
compression, sudden loss of
contact breaker points gap
crankcase breather, test for
crankcase breather pipe
crankcase oil, changing
crush, cyl head and PRTs
cylinder base bolts, removing
cylinder block & tappet blocks
cylinder block, honing and replacing
cylinder block, painting
cylinder block, removing old gasket
cylinder head bolts, leaking
cylinder head bolts, re-torquing
cylinder head bolts, torquing
cylinder head, cleaning
cylinder head "crush" and PRTs
cylinder head, removing old gasket
distance pieces, rear axle
electrical, Pazon ignition
electrical, schematic diagrams
electric wiring color codes
engine mounting plate fasteners
engine sprocket, align w duplex sprocket
float and float needle
footpegs and brackets, passenger
forums, British motorcycles
front fork, alignment
front fork, dismantling
front fork gaiters
front fork oil
front fork, remove as unit
front fork, remove legs separately
front fork seals, replacing
front wheel bearings
front wheel brake
front wheel brake shoes, illustrated
front wheel fender brackets/stays
fuel lines, plastic and safety
fuel lines, removing carbs with
fuel lines, removing connectors from gas taps
gaiters, front fork
gaskets, removing old
gas tank, paint schemes
gas tank sealers/liners (link)
Gas taps, removing & replacing
Gas taps, sealing
gear cluster, installing into gearbox
gear oil change
gear oil & yellow metal
gears clash engaging first, avoiding
gears clash engaging first, causes
gearbox assembly: three methods
gearbox problems - resources
gearbox, indexing camplate & quadrant
gearbox inner cover
gearbox inner cover, removing
gearbox inner cover, replacing
gearbox jumping out of gear
gearbox outer cover
gearbox outer cover, removing
gearbox outer cover, replacing
gearbox, power transmission illustrated
gearbox, removing bearings from casing
gearbox, replacing bearings in casing
gearbox, replacing inner cover bearings
gearbox, sealing inner/outer covers
gearbox tear-down notes
gearshift camplate positions
General Data T120/TR6
General Shop Info
grease gun, mini
handlebars, shock absorber mounting
handlebars, removing bonded bushes
Head bolts, see Cylinder head bolts
head gasket, annealing & installing
headlight bulbs, breaking
headlight bulb LED/Halogen replacements headlight reflector/lense fixing wires
headlight shell wiring diagram
heating cases & other parts
heat insulation, carbs
horn/dimmer switch harness routing
idle screw o-ring
ignition coils, installing
ignition coils, heating up
ignition coils, replaced (Bonnie)
ignition coils, testing
ignition coil wiring connections
ignition switch connections
indexing gearbox camplate & quadrant
Issues, history of
kickstart lever tapered pin
layshaft end play, measuring
layshaft thrust washer locating pegs
Loctite products, stick form
Loctite, where to use (John Healy)
Lucas wiring color codes
main bearings, replacing
mainshaft bearing, replacing in inner cover
mainshaft/layshaft bearings, removing
mainshaft/layshaft bearings, replacing
needle jet pin gages
O-Ring Sizing Chart
o-rings, carb to intake manifold
o-rings, dimensions for prt seals
o-rings, front fork dust excluder sleeve
o-rings, idle & air screws
o-ring & insulation block carb mounting
o-rings, push rod tubes
o-rings, swinging arm
o-rings, rocker arm spindles
o-rings, tach gear housing
oil, zinc content
oil breather line
oil, changing crankcase
oil leaks, drain bolts
oil pressure switch
oil pressure relief valve
oil seal, D.S. crankshaft
Oil tank, 1966 defective design
oil tank, reinstalling
parts lists, factory
parts lists, Hermit's
part numbers, conversion of
parts supplier list
patent plate, replacing
Pazon Sure-Fire PDF
Pazon, schematic diagram
Pazon, setting timing with
pilot air screw
pin gage for needle jet
pinion gear removal
piston rings, gapping
piston rings, installing
piston rings, orientation
Podtronics voltage regulator/rectifier
points, contact breaker gap
pressure plate, adjusting
primary chaincase gasket
primary chaincase oil, changing
Primary Chain. adjustment
primary chain wear, checking
primary chain wear, photos
pushrods & rocker boxes, replacing
pushrod tubes (PRT)
pushrod tube o-rings
pushrod tube seals
pushrod tube o-ring & seal dimensions
pushrod tube seal "crush"
pushrod tube installation
Rear Chain, adjusting slack
rear chain, checking wear
rear chain, cleaning
rear chain, removal
rear chain, replacement
rear chain, lubrication
rear wheel alignment
rear wheel bearings
rear wheel brakes
rear wheel brake shoes, illustration
rear wheel brake shoes, centering
rear wheel fender
rear wheel fender brackets
rear wheel, removing
rear wheel, replacing
relief valve, oil pressure
removing old gaskets
re-torquing head bolts
rocker spindles, assemble
rocker spindles, types of
rocker arm spindle o-rings
rocker box gaskets
rocker box gaskets, lightweight pr mod
rocker boxes, remove
rocker boxes, replace
rocker clearance, adjusting
roller bearing conversion for steering neck
rotor, loose center
rotor installation guide
rotor nut, torqueing
rotor to stator clearance
selenium rectifier connections
serial numbers, 1950-1969
serial numbers, 1969-1983
shock absorbers, rear
Speedometer and Tachometer
speedometer gearbox lube
speedometer gearbox ratios
sprocket, gearbox - replacing
stanchion tubes, replacing
stator installation guide
stator to rotor clearance
switch, Lucas 35710 - wiring diagram
switch, brake light (rear)
tach cable, lubrication
tach drive gearbox, removing
tach drive gear, lubrication
Tappet guide blocks
Thackary spring washers
thrust washer (clutch)
thrust washer (clutch) and GL5
thrust washers (gearbox)
thrust washer (rocker arms)
timing cover, removing (link)
timing, see Ignition timing
tires, Dunlop technical reference (PDF)
torque settings, head bolts
torque stays, engine
trip meter handle won't turn
valve clearance, adjusting
valves, replace in head
voltage rectifier/regulator, Podtronics
wiring, Lucas color codes
Wiring diagrams, electrical system
wiring diagram, headlight shell
wiring harness, horn and dimmer switch
wiring harness, rear brake switch
wiring harness, removing (stock)
wiring harness, removing
wiring harness, routing
Workshop manuals, factory
wrench jaw gap sizes
yellow metals & gear oil
zinc, in motor oil
That's All She Wrote