Bonnie's Maintenance Log

Triumph makes a mechanic out of a man
Beginning of Log

Field Guide to the 1969 Triumph Bonneville


Random Note - Front Fork Nuts

There is a Triumph part number (97-4166) for a large washer for fitment beneath the front fork cap nuts. Available from Klemph for $2.50, from Baxter for $0.25. Seems to have been introduced in 1970 - new 650 forks with internal springs.

Complete Rebuild 2021/2022/2023 86,000 miles







Additional Seal, Washer Replacements


Crankshaft, Prior to Damage

February 7, 2022: Transported engine to LD for parting crankcases.

February 12, 2022: Transported engine to PL to remove bearing race and ultrasound cleaning

Crankshaft, After Damage

DS damage discovered May 29, 2022 during final assembly.

Winter 2020/2021

Transmission Teardown

85,022 miles

Engine sprocket, clutch center, sprocket, plates (steel & friction) have 100 miles short of 20,000 miles (replaced at 65,120 miles) and they all look pretty good.

The duplex chain is beginning to have some stretch. I replaced it at 78,976 miles, so it has just over 6,000 miles on it.

Loose Stuff

Next Oil Change

Caution!86,000 miles

11 November 2020

85,022 miles

Oil change. 1,322 mile interval - Bad Boy! But oil was still cleanish - clear/brown.

Primary drain bolt was a bit loose. As was the rear battery strap nut.

Last few oil changes it seemed like I took more oil out of the primary than I'd put in. This oil change confirms that is the case. Previous oil change I filled primary with 330 ml and today I drained 375 ml.

Crankshaft DS seal? Since last oil change I'd added a bit over a pint of crankcase oil. The primary chaincase has been completely oil-tight.

24 October 2020

84,824 miles

Ran over oil change mileage on yesterday's ride. Gonna wait and see impending snow forecast before changing right away. I'm sure Bonnie won't mind.

14 October 2020

84,340 miles

Voila! A new motorcycle! Feels and sounds less heavy and plodding. Throttle response back in sync. Low-speed under load coming up hill is way smoother.

Somewhat shocked by amount of black sediment on drain bolts. Didn't clean carbs last winter!

27 August 2020


Oil Change.

I added 20 oz of crankcase oil during the 1,000 mile interval of last oil change. That's definitely less than I was using last year.

Primary chaincase is definitely not leaking! Replaced drain plug with new washer and used sealant on both sides.

Removed K70 was installed in January of 2019 @ 79,006 miles, so it gave me 4,675 miles of service. About average mileage.

3 August 2020

83,390 miles

Added 8 oz oil to top up to Full line. Have added 20 oz thus far on this oil change.

Checked tires - front ok, rear back down to 28 - (hadn't refitted valve caps last time). Re-inflated to 31/32, replaced valve caps. Should re-check soon.

Tune's been on and off and has settled for now on 'pretty good'. I touched nothing except valve lash last week. Twice near end of Tuesday's ride she died going down to idle at a stop - of course that was after blasting up Ste-Cat-in-the-hat hill and coming to a fairly quick halt at the top. Until now I had 100% confidence of no low-speed stalls.

28 July 2020

83,262 miles

Adjusted valves. DS Intake was tight.

After weeks of near perfection in tune, Bonnie doesn't have that same perfect smoothness on the throttle, up and down, and she recently stumbled a couple of times at low & high rpm. A cold start at the Castle took two kicks one day recently.

Just changed from 94 octane (Orford PC) to 91 (Burrough's Falls PC). Also noticed degraded performance using Crook's 91. Ran super good before on 94. Could be a gas thing. If so, is it octane or quality? Moisture? Too, I have to consider that I'm using gas from containers sitting in the tractor shed. But that was true before also.

6 July 2020

83,198.1 miles

Added 2 oz of oil.

The end of the DS exhaust tappet spindle had a light film of oil and road dust. I wiped it clean and I'll check to see how long it takes to weep again.

And as usual there was a bit of oil sitting on top of the tank. Beginning to wonder if perhaps the cap needs a new gasket?

Both tires were a little soft, I put 32lb in the front and 31lb in the rear. http://www.britbike.com/forums/ubbthreads.php/topics/663044/re-tire-pressures#Post663044

6 July 2020

82,897 miles

Topped up crankcase oil with 150 ml. So 5 ounces over 195 miles, which would be approximately a bit more than 3/4 of a quart per 1,000 miles. A bit less oil consumption than last year, I think.

24 June 2020


Oil Change. Changed crankcase oil & filter and primary chaincase oil and cleaned chain.

Somehow managed to drag the chain off the gearbox sprocket and spent ah hour-and-a-half getting it back on. Then another hour-and-a-half cleaning up the mess left behind.

Over the last 1,000 miles she used very little oil. I topped up twice, but very little both times - maybe about a cup of oil altogether.

Only 200cc of oil came out of the primary chain case, but it was only draining for about four hours so it probably hadn't fully emptied yet. I added 10 ounces of new oil.

8 June 2020


Checked crankcase oil upon return from ride. Went from the top "L" in Full down to the full line - so pretty negligible oil consumption over the last 259 miles.

8 June 2020


Checked valve clearance prior to going on a ride. Intakes are probably very slightly wide, but from experience I know it'd be hard to get less gap without it closing up, so I left them as is. The exhaust gaps were slightly less open then I usually set them, but that probably just means they are closer than usual to the official 4 thou, so I left them alone also.

ARe-synced the cables as the TS was lifting slightly in advance of the DS.

The Bonnie ran strong and smooth on the ride.

4 June 2020


Mufflers finally arrive from Walridge.

Not excessively pleased with the new mufflers. "Made in England" stamped into the backs of them, but the forming just behind the intake is poor compared to the other two sets I have, the exhaust ends have a slightly rough finish, and the seams in back are visible (off, not on the bike). And most dissapointing of all, they are louder than the previous set. I guess that's all you get for $300 these days. Wonder if the cheaper Taiwanese units were actually better quality?

19 May 2020


During yesterday's ride a mounting bracket cracked and the TS muffler fell off in Saint Etienne de Bolton. New set of mufflers and brackets on order from Walridge.

Idle is getting wonky and she stalled twice coming to stops on yesterday's ride. First time this season she's done that.

15 May, 2020

81,999.0 miles

Rear chain adjustment

Still running quite well, although the warm idle speed has increased to around 1400 and de-accelerating is less and less smooth.

I added about a half-cup of oil to the resevoir and it brought the level up to exactly what it was at the beginning of the season - to the first 'L' in 'Full' on the stick.

After 376 miles there is still not so much as one drop of oil on the Castle floor, although for the first time this year there was 'mayonaise' on the floor - about 1/4 teaspoon. So 4 oz of oil in 376 miles would project out to less than 12 oz of oil per thousand miles. I think this is a little less than she used last year, so maybe the rings are finally bedding down?

7 May 2020


Adjusted rear brake, checked tire pressures. So far not a drop of oil has shown up on the shop floor. But sometimes takes time to saturate and drip. I also succeeded in banishing the TS fuel leak - a loose clamp on connection to banjo bolt. The TS is now so clean all the time!

Previous carb hesitation is gone after syncing cables, but it's not quite as smooth on de-acceleration - a slight burble-burble thing. Mixture?

2 May 2020

(81,739 miles)

Second ride: 50 miles.

Pre-ride, TS carb was going first so I started to sync it to DS. Was taking way too much adjustment so I looked around and found the ferrule on top of the TS carb was mostly pulled out of the carb. Is this why I have to perpetually sync the cables? Replaced ferrule, re-adjusted.

Made a bolt check and found both the clutch and front brake hand lever controls were about to fall off - don't think I ever tightened the fasteners after putting back the old parts I'd removed in anticipation of replacing them with the new parts which are stuck at the us address.

Adjusted clutch and front brake cables and the mirrors.

29 April 2020

(81,664 miles)

2020 Maiden Voyage.

First kick got me a wicked kick-back, but the Bonnie started on the second. I went easy on the throttle blipping but kept rpm's above 1,200. Whenever I let the throttle go slack she idled without stalling, which surprised me! In fact, cold and hot the idle was very dependable between 900 & 1100 without stalling, even once! Now I'm amazed! Slight bog on acceleration and de-acceleration - will sync the carbs.

28 April 2020

(81,664 miles)

Oil Change. Crankcase and primary chaincase oil & filter.

Checked primary chain tension and found 3/4" slack. Strange because I remember adjusting it during the fall. When I tried using the adjuster tool it didn't seem to engage the adjusting screw. Something wrong, so offed the primary cover and discovered that the 'slipper' had cracked in two.

Re-installed the original part, adjusted for 3/8 slack, and buttoned the primary back up (Hylomar on both sides of gasket as last time - gasket won't be re-usable, but no leaks!

15 April 2020

(81,664 miles)

Not all that much to do on the Bonnie this winter. I puttered around in the Castle on and off all winter. Mostly cleaning and polishing. Sunglasses now mandatory at the Castle!

Also updated my inventory program to include a bin number for each part. After taking an inventory and re-arranging the parts rack I printed out all new tags with bin numbers. Now I can find any part quickly and easily and I always know where to return part bags after using them!

I ordered new control levers (pivots on originals are so worn and loose that they flap in the breeze over 15 mph), a new chain, and a few other parts on the 17th of March. They arrived at my VT pob one day after the Canadian/US border was closed to traffic so there's no telling when I'll be able to pick them up.

2020 winter to-do list

On indefinite hold:

Remounted the Podtronics under the battery carrier to be a little more forward to eliminate interference with rear fender. Used screws & nuts instead of wire ties to be sure it stays put. Compensated for screw heads beneath battery by using two layers of rubber padding. Remains to be seen if this leaves sufficient clearance between the seat and the top of the battery.

The rear battery carrier strap was badly worn by vibrating contact with the battery last year. All the batteries I've used have been 3-1/2" wide so unsure why the problem just cropped up. When I can order from the States again I'm going to pick up a Motobat AGM MB9U which is just 3" wide.

I tried getting a new battery carrier 'strap' (82-8028) but I ended up returning it because is was badly formed and I wasn't about to take a torch to a brand-new $30 part. All vendors seem to have the same crappy stock.

Finally I remembered that the oil tank and side cover I bought off E-Bay also included a battery carrier and the front and rear straps - used old stock fits perfectly! I made the purchase to have a back-up oil tank when the original developed a leak. Danny Guay did a great repair on the original oil tank (barely touched the brand-new paint job!), but the $65 E-Bay purchase is looking real good now!

Installed the new center stand. New stand from British Only (RIP, we miss you!) is the correct part which replaces the older style that Bonnie came through with. Now I'm using the correct mounting hardware that I kept buying for the old stand and wondered why it never fit!

15 October 2019

(81,050 miles)

New K70 3.25 x 19 tire mounted by Thibault. $147.98 for tire ($123 plus tax). Glue-on weights 'cause that's all they got. Service manager is sending old badly warn tire to Dunlop to see if they'll replace or ?

10 October 2019

(80,873 miles)

Received wheel balancing weights and balanced the front tire on the bike. Had to use quite a few weights. After balancing the wheel I inspected the tire tread wear and realized that the weights are compensating for very heavy abnormal wear around half the tire.

illustration of tire wear and wheel balancing weights

4 Oct 2019

80,637 miles

Oil Change

Much quieter after chain adjustment. Went from 3/4" slack to 3/8".

And shifting is much smoother after adjusting clutch rod from 3/4 turn out to 5/8" slack.

27 Sep 2019

80,490 miles

Screwed up and didn't check primary chain tension until after I'd refilled with oil. The chain's a bit on the loose side.

The centerstand is the one that came with Bonnie - a 1968 part number and used the older mounting hardware (shouldered bolt, tab washer, lock nut. The cross-bar weld broke on the DS.

Ordered 1969/70 centerstand, for which I already have plenty of hardware (and I always wondered why the nuts and bolts I ordered never fit!).

22 Sep 2019

80,356 miles

Topped up oil with 200cc before leaving for trip around Lake Memphremagog.

20 September 2019

80,114 miles

Added 375cc oil before departing for a day trip to East Randolph/.

New centerstand broke in half and dragged on roadway.

16/17 September 2019

80,031 miles

Returned from two-day trip to White Mountains.

15 Sep 2019

79,716 miles

Pre-flight check-up for ride down to White Mountains

8 Sep 2019

79,632 miles

5 Sep 2019

79,481 miles (plus 530 un-clocked miles = 80,011 actual miles and time for another oil change)

Finally got out for a short run in the evening. Seven Celsius upon return, time to put the liner in the riding jacket! Bike's running decent, but throttle could be smoother on de-acceleration. On the bright side (finally a bright side), the rocker box oil leak has been banished!

4 Sep 2019

79,456 miles

Checking valve clearance I found the TS exhaust rocker completely loose - I must have missed tightening the nut on the adjuster pin! The pushrod was right off the rocker so I stripped everything down a second time, re-positioned the pushrods, put on a new gasket, and replaced the rocker box. Whereas the job took me just under 5 hours the first time, it only took two-and-a quarter hours the second time.

3 Sep 2019

79,456 miles

When re-assembling the rear wheel I used a new TS distance piece (37-1477). John Healy says this piece should be 1.055" to 1.060" long. Bonnie's original one is 1.042", and the new one is 1.048".

After completing the work I rolled the Bonnie out into the orchard and put a little more oil down the cylinders. After pumping the kickstarter to clear excess oil I put in a brand new set of NGK B7ES, primed the gas, and commenced kicking. She made me work for it, but after a couple of patient pauses she finally started up, and then commenced to pollute the entire Northern Hemisphere with smoking burning oil.

A ride down under bunker was thrilling, but the exhaust valve clearance was excessive and the exhaust tone has a strange sound to it - kind of low and flat. Then on the way back she wouldn't take a lot of throttle without bogging, although sufficient to make it back up my road to the Castle.

Back at the Castle I checked the plugs (they looked ok) and also verified that the carb slides were working properly. The cable synchronization was a wee bit off and I fiddled with that until it was perfect. Tomorrow morning I'll re-adjust valve clearance and take it for another test ride if it's not raining.

2 Sep 2019

79,456 miles

Right off the bat I had trouble getting the exhaust valve inspection caps off - never had that happen before. As it happened they came right off with a little heat from the propane torch.

12 Aug 2019

Stripped down far enough to remove exhaust rocker box and replace gasket due to pesky oil leak on exhaust TS. I should have used baby powder before I had to park the bike - hard to tell, but seems to leak at rocker box/head joint just below the valve inspection cap. But maybe also from the domed nut on the oil line to exhaust rocker spindle, or does that just catch the fine 'spray'?

Hunch is that this might be because when I re-torqued the head bolts after last re-installing the head, I got lazy and didn't bother removing the tank, coils, and head steadies in order to re-torque the inner 4 head bolts. 'Ahhh, they'll be ok, they're held down by the head steady nuts, right?'. Wrong. Being locked with another nut of course has nothing to do with they're needing re-torqued after a heat cycle or two.

So the intake side was ok, but the exhaust leaked copiously - at the end pooling up on engine fins every 30 miles or so.

Also polished the original headers - Wow! Nice chrome! Tempted to put them on - supposed to be a little more quiet with the balance tube - I actually wouldn't mind that, even if the tube is ugly in my eyes.

5-12 August 2019


4 June 2019

Speedo gearbox imploded.

For oil change interval, additional mileage before parking: 332 miles.


12 May 2019

79,006 miles

Pre-season ride - Katevale/North Hatley/Katevale.

Beginning of Season 2019

13 May 2019

79,053 miles

Registered Bonnie and rode to Magog/Ayer's Cliff/Lennoxville/North Hatley.

10 May 2019

79,006 miles

Oil Change. Oil and filter, crankcase and primary.

Rainy day, finally laid off clearing trails long enough to get some work done in the Bonnie Castle.

After completing the work I removed the Bonnie from her winter throne, backed her over to the doorway and after a tickle she started up and ran on the first kick and ran like a clock.

Using the New Thin Wrench & Replacing the Rear Wheel

Re-installing the rear wheel I got to use the new thin wrench on the inner axle nuts. I had to buy a complete set (made in India I think, $70 Cdn at auto parts) and then have the largest wrench (1-1/4") enlarged to 1-5/16" by a Magog machine shop ($15). Definitely worth the time, effort, and money - replacing the rear wheel was never so easy!

The thin wrench makes it possible to tighten the inner axle nuts in place, on the bike, so no more trial-and-error. Now it's easy to align the speedo gearbox in place while tightening up the inner nuts. And so much easier to center the brake shoes applying pressure with the brake pedal with wheel held securely in the frame.

Ain't it sweet when the tool does the job?

Ravenol Gear Oil

The Redline gear oil I used last year (Red Line 50304 MT-90 75W-90 GL-4 Manual Transmission & Transaxle Lubricant) was ok, but shifts didn't feel as smooth as they should. This year I'm trying a Ravenol product. It's 'Neutral to metals' and 'no foaming', which I take to be a good thing. And it comes with a built-in 2-section telescoping tubular spout that takes all the hassle/mess out of filling the gearbox. Amazon description:

"Ravenol Multipurpose Gear Oil SAE 80W-90 GL-4 is an EP (extreme pressure) gear oil for manual transmissions, transfer cases, steering gears, and axle drives under standard conditions. Contains highly refined base oils that are paired with a balanced additive combination. These ensure a high load carrying capacity, wear protection, and oxidation stability are all guaranteed. Due to a superior viscosity-temperature behavior, low pour points, and the elimination of foam formation, the oil can be used in a wide variety of operating conditions.

Technical Characteristics and Features:
- Very good adhesion & pressure resistant lubricating film even high loads
- Excellent oxidation stability
- Optimal viscosity-temperature properties
- Provides an anti-wear effect
- Good air release characteristics with no foaming
- Neutral to metals and sealants used in transmissions and differentials

28 March 2019

79,006 miles

Removed rear chain and checked stretch: 5/16". This is well within the acceptable wear parameters according to the workshop manual, but I think the workshop manual's maximum wear spec is way past what would be harmful to sprockets, something pretty much confirmed by a query on TriumphRat.net.

Tried once again to find a Tsubaki chain but could only find o-ring chains by them so I ordered a DID chain.

12 February 2019

Drained gearbox and recuperated 400ml of the Red Line gear lubricant.

After sitting for a couple of weeks the Red Line lubricant on top was very clear, but the bottom layer was gray with metal. I suppose this is "normal" wear.

So Bonnie lost 100ml of gear oil while covering around 3,000 miles. Where'd it go? My money is on the thru-hole in the gearbox casting for the shifting fork shaft. I thought I could seal it after assembling the gearbox, but couldn't get to it afterwards with the gearbox sprocket in place.

12 January 2018

New K70 rear tire mounted by Thibault, Sherbrooke. Sixty-eight bucks for a tire mounting, maybe I should start changing my own tires, but how to balance?

End of Season 2018

79,006 miles

5 Oct 2018

78,976 miles

Removed leaking float chamber bowel on TS carb - reassembled using Hylomar on gasket and it seems to have stemmed the flow.

14 Sept 2018

78,292 miles

1 Sept 2018

78,019 miles

Adjusted carbs

30 August 2018

77,957.1 miles

Pulled off the center stand. None of the #7 Parts pivot bolts/nuts/tab washers I have in stock fit this stand so I began researching center stands. I came up with a table of stands and mounting hardware for 650s from '64 to '71.

Based on that info I have deduced that Bonnie NC00125 came equipped with an 82-5692 center stand. The 82-5692 stand was supplied with '64 to '68 650s. Maybe Frank changed it, but it's also quite possible that the factory was using up the old style stands at the very beginning of the '69 production.

I have the appropriate hardware for the 82-5692 stand on order - hoping it all fits together.

Table: Triumph 650 Center Stands & Mounting Hardware

28 August 2018

77,957.1 miles

TR7RVMan (BritBike.com) thought the problem might just be fuel washing the rings. I took his advice and poured a couple of tablespoons of oil down the plug holes, cranked several times to blow out the excess oil, replaced the plugs, and low and behold the Bonnie had compression again and started right up.

I celebrated with a ride over to Montgomery and the northern Greens (156 miles).

By the time I got back I had no tailight or headlights and when I tried to put the bike on the center stand in the Bonnie Castle the stand crumpled and she fell over onto the timing side - luckily caught by myself and a couple of horses.

What next? I wonder.

The 'perfect' tune I had three weeks ago has vanished. Low-speed running fairly decently, but not as well as before and the engine died every time I tried to idle it.

26 August 2018

77,811.7 miles

Oil Change. Crankcase oil change only, no new filter.

Got the oil tank back from Danny Guay on Friday afternoon. Stacked firewood all day Saturday and Sunday I put the oil tank back on.

Filled the tank and rolled the Bonnie out into the yard to take my first ride in just over three weeks. Tickled the carbs and kicked her over. Kind of fired once and then died out when I gave some throttle. I started pumping the kickstarter to get to the next compression stroke but it just kept kicking through.

There's hardly any compression - more than if the plugs were out, but not much. I checked the valve clearances - ok, so all 4 were a bit on the wide side and I readjusted them.

Still no compression.

The bike was running nearly perfectly when I parked it just over three weeks ago.

31 July 2018

77,811.7 miles

Began unbolting oil tank in an effort to figure out the mounting problem. I found the problem - the forward top bracket has snapped off. Actually I think the breakage was the end result of some other problem.

I'm not a 100% sure, but here's my theory:

when I reinstalled the tank this spring I used all new rubber parts and being new their inner and outer dimensions made for very tight fits. In my own inimitable, clumsy way of doing things I failed to seat the rubber jug fully into the rear tank mount. I found the tank to be too rigid as I bolted it up, but I put it down to the new bigger diameter oil lines which bump up against the backside of the engine mounting plate. After discovering the contact between the tank and the fender I rotated the bottom mounting bracket for best clearance. That must have further stressed the front bracket because it snapped off within 50 miles of my "adjustment".

The tank is unbolted, disconnected, and draining in place, but this looks like the end of the season to me. I have not a clue who I can trust to make this repair. And even if welded by skilled hands, what are the chances it will still fit afterwards?

Such a bummer - the Bonnie is looking like a million bucks and running like 2 million after a two-day marathon of clean and shine and tune and re-tune in preparation for this weekend's ride to Ormstown.

30 July 2018

77,701.0 miles


The vibration noise I've been hearing is not the coils, it appears to be the oil tank rubbing on the rear fender. I tried adjusting it but it didn't help much and I think the tank mounting is kind of stressed the way it is.

Somehow the tank has moved rearwards - I can now put TS air cleaner on and off without taking it apart, but now the tank rubs on the fender. I must have it somehow mounted incorrectly, but I don't see how.

I've been running the engine retarded ever since reinstalling the Pazon this spring. When I went to rotate the Pazon a tiny bit counterclockwise it just sort of found its own new spot. When I checked with the light the timing was perfectly on. I left it there. What a difference! Twisting the throttle now lifts the handlebars and throws me back on the seat.

With only a thousand miles so far this season, and no oil leaks, the Bonnie is still pretty clean from its winter teardown, but being how I'm going to the Mtl CMVG Ormstown rally this weekend I took it to the car wash and then came home for a shining and polishing session.

I tried to make corresponding reference marks at 4 o'clock on the Pazon disk and the inside of the timing case by applying red nail polish and then scratching a line across both. Didn't work - not enough contrast against green disk. Also got too much nail polish in there - may have glued down the disk. Looking for a better way.

13 July 2018

77,432. miles

Nice 105mi. ramble down to Mansonville (scenic gravel rout), and then Dunkin, Glen Sutton, Abercorn, Brome, Ch Stagecoach to South Bolton, Ch Mountain to Knowlton Landing, Austin, Magog, AC.

Bike is running pretty decently. I've adjusted valves 3 times since the bike came off the table. Adjusted carb low-speed 3 times also, and have synched carb cables at least 6 or 7 times (new cables stretching?).

The big surprise is that the Bonnie is leak-free! In spite of having not put sealer on mainshaft splines or the shifting fork rod there's no oil coming out of the gearbox. Or the chaincase! Or the crankcase and new oil lines. Not a drop of oil on the Castle floor! The drive side intake rocker shaft is weeping a tiny oil smear after longer rides, but a swipe of a rag takes care of it. The exhaust rocker box was weeping just a little between it an the head, but I re-torqued it and all is well there.

(Official) Beginning of Season 2018

2 July 2018

76,994. miles

Registered the Bonnie for 2018. Over the past month I've taken a couple dozen evening rides up to Ste Cat and one foray down to Seymour, Island Pond, and Willoughby.

Beginning of Season 2018

8 June 2018

76,606.7 miles

First ride of the season - Ste Cat.

Winter 2018 Tear-Down

6 June 2018

Bonnie comes off the table

After fitting everything but the seat, tank, and fuel lines I took Bonnie down from her winter throne. After looking at her two feet off the ground all winter she looks weird sitting on the floor - very low!

After adding the gas tank and new fuel lines I tried priming the carbs. The TS carb overflowed. Took it apart and found a lump of goo on the needle. Worked fine after reassembly. Then it was the DS carb's turn to overflow. Found nothing wrong taking it apart but it still overflowed after reassembly. Took it apart again and decided to change the bowl, the needle, and the pin. As I reassembled I noticed that the gasket was holding the bowl down. Took a razor to the gasket and then all was good. I should probably take apart the TS carb again and modify the gasket.

So I rolled her out of the castle and she started right up on the first kick.

This morning I'm on my way back over to the castle to:

30 May 2018

Loctite used on:

Winter 2018 Service & Parts Replacement (76,606.7 miles)

March 2, 2018

Pulled the engine out of the frame three days ago. Used a floor jack to keep the engine suspended while I removed the front and bottom engine mounts and then wrapped my arms around it and pulled it out from the left side with an upward motion, then a tilt towards myself, and then up and out.

Have been cleaning up and inspecting everything. Findings thus far (not including all the bronze in the gearbox):

Andy Hansen is shipping back my repaired speedometer. I asked him if I'd over-lubed it or anything like that. His reply:
"What had failed on your speedo was the drag disk. It is an aluminum disk that is captured by the magnetic field and transfers the motion to the pointer. The shaft through the drag disk had become loose. It appears I had used a new drag disk originally and this was simply a part failure.
I advise against using oil on a cable and recommend grease because the oil can "corkscrew" its way up the inner cable and into the instrument. However, your instrument was clean and dry inside with no evidence of oil entering it."

January 25, 2018

Pulled off gb outer cover and found lots of bronze 4th & 5th photos down).

Oil reservoir and oil lines removed.

Removing oil bottle - remove battery carrier and push reservoir towards DS before twisting and removing.

Scheduled Maintenance & Repairs

End of Season 2017

9 November 2017

76,606.7 miles

19 October 2017

76,124 miles

Changed crankcase/primary oil/filter

Cleaned and lubed chain

Discovered source of leaking fuel - the screws holding on both float bowls were so loose that gasoline was oozing out. Getting much better gas mileage now and also better starts.

Also discovered that although both carb slides were lifting simultaneously, the left slide was starting from higher. After resetting and re balancing them from scratch the Bonnie is running superbly - silky-smooth acceleration and deceleration, more power, and an exhaust tone that is raw and ripping and smoothly melodious at the same time.

Primary chain oil:

7 October 2017

75,943 miles

Received and installed two 6v. Taiwanese ignition coils. Bonnie started on first kick and ran fine on both cylinders. But I need to redo the carbs after I fidgeted with them on the trip.

2 October 2017

Broke down in Montpelier, trying to get back home from Rutland with right cylinder misfiring. New plug didn't help. Right cylinder ran on left cylinder plug lead so my diagnosis was ignition coil.

LA drove down in the truck and hauled me and the Bonnie back home.

Apart from the time I didn't replace the master link clip and had to be towed home from Stanstead this is the first time that Bonnie left me on the road. Not bad for 71,000+ miles.

1 October 2017

75,633 miles

In advance of second trip to Green Mountains:

Synced carbs, adjusted valves, and checked ignition timing.

DS exhaust valve has been on the wide side all summer and I got it back in the same ballpark as the TS. The ignition timing was right on.

12 September 2017

74,955 miles

Changed crankcase/primary oil/filter

Cleaned and lubed chain

10 July 2017

74,012 miles

Changed crankcase/primary oil/filter

3 June 2017

Watched a Lunmad youtube on adjusting ignition timing and valve clearance this morning. Both threw me for a loop, had me thinking I'd been doing all wrong all this time. Certainly a plausible posit.

The Ignition timing mixup turned on Lunmad's timing mark representing TDC while Bonnie's represents 38 degrees BTDC.

The valve clearance thing -

Lunmad opens DS Intake valve (rocker all the way down) and then adjusts the DS Exhaust valve clearance. Etc.

When I adjust DS Exhaust valve clearance, I open the TS exhaust valve (rocker down).

After my initial panic I realized they must be the same thing, mechanically speaking.

But after I re-adjusted clearance, Bonnie wouldn't start. Was it the valves? Or was it the sooty spark plugs that I wired brushed and blew out by mouth? I dunno.

I removed tank and checked all clearances. All ok except the DS exhaust - which seemed a bit tight. I readjusted it and the Bonnie started, stubbornly. By the time I got to the bottom of the driveway and turned towards Parkes, it was firing on one cylinder. I turned around but then the other cylinder started firing until it seemed ok. Ran fine for a 40 mile run and started fine.

2 June 2017

Service (73,011 miles)

Finally found the source of my downshift 'buzzxx' noise tank noise. It was the oil pipe to the rockers. It was too proud of the frame and evidently vibrated against the inside of the frame even though it left no witness marks that I could see. Hmm. Not saying much these days, I need glasses! I tie-wrapped it closer to, but not touching the frame and it banished the buzz!

Beginning of Season 2017

5 May 2017

72,200 miles.

First ride of the season.

Changed crankcase/primary oil/filter

Winter 2016/Spring 2017

No significant work carried out this winter

Note on Bonnie's Gearshift & Gearbox Components

Since work carried out in April 2016 and June 2016, Bonnie is using the following gearshifting and gearbox components:

End of Season 2016

22 November 2016

72,190 miles

Snow and salt.


August 11, 2016

71,000 miles

Changed crankcase/primary oil/filter

July 10, 2016

69,950 miles


June 27, 2016

69,600 miles


Still working on jumping out of gear problem. Pulled off gb outer cover and replaced gearshift quadrant with new unit from Baxter. Before removing original I made a mark on the case at the furthest extent of down-shift traval. As soon as the new quadrant was in I could see that in downshift it went about 3/32" further than the original and I knew I was onto something good.

After putting everything back together, a quick test ride confirmed that the problem was gone - downshifting is crisp and clean. No more downshift malfunctions, and first gear no longer pops into neutral when descending the steep driveway hill in gear.

Victory! After two years.

June 25, 2016

69,575 miles

Persistent oil leak, pooling on top of gearbox. Could be a) chaincase port for alternator wires, b) PRTs, c) that base gasket with 'just a tiny tear' I used during winter reassembly.

Talcum powder took me straight to the culprit base gasket. First base gasket leak ever. Will I ever use a torn gasket again? Anywhere?

Dismantled the top end and replaced the cylinder base gasket, leak cured.

Base and rocker box gaskets were from Baxter and labeled "Coventry Spares". I don't think these are the highly praised "Covseal" rocker box gaskets, but maybe.

Both base and rocker gaskets had wire in them. I've been more and more inclined to use paper gaskets without wires, so it will be interesting to see how well these hold up.

[February 2018, 76,606 miles: have to remove rocker boxes to take engine out of the frame for machine work (gearbox thrust washer locating peg & new roller bearings/seals/etc. After 7,000 miles the rocker boxes were still 100% leak-free (as were the PRTs)]

Work Times

February 2016

Winter Service & Repairs (68,876 miles)

I used Loctite on the rotor and kickstarter ratchet nuts , but I failed to use it on the clutch nut.

I also used Loctite on

Trap door - I replaced the countersunk screws holding on the trap door. I noticed last year that one of the screw hole's threads were stripped. It's the one at 12 o'clock. I slathered it with blue Loctite and tightened it down as much as I dared.

Major work

End of Season 2015

68,876 miles

November 15, 2015

68,876 miles

September 15, 2015

67,400 miles

New front and rear K70 tires with new inner tubes (all from BikeBandit ($174 total).

Mounted by Jeff Price, Cycles Unlimited Newport

September 12, 2015

67,100 miles


September 5, 2015

Removed outer gearbox outer cover and put back the original pawls and guide plate. Goes into first gear every time from a cold start now, but on the road it still hangs up in neutral when downshifting to first gear and pops out of first gear after that.

As bad as it is, this configuration seems the best after last winter's teardown.

September 3, 2015

Removed outer gearbox and put the new pawls back into the gearchange quadrant. This is the second time I've put them in and the result was the worst gear shifting since the first time I put it all together last spring. Problem getting into first gear nearly every time, and popping out of gear - 1st 2nd and even 3rd.

August 25, 2015

Re-checked timing - still ok.

August 17, 2015

Checked ignition timing and found it was very retarded. Re-adjusted.

August 11, 2015


Changed crankcase/primary oil/filter

June 2 2015

65,740 miles

New drive chain - D.I.D. from Bonneville shop.

Beginning of Season 2015

65,120 miles.

All lubricants changed after completion of winter work

Winter 2015 Tear-down (65,120 miles)

Winter 2015 Service & Parts Replacements (65,120 mi)

Machining services by North Country Engineering

End of Season 2014

EOS Mileage: 65,120

2014 Issues

September 29, 2014

64,150 miles

Changed crankcase/primary oil/filter

I've taken quite a few rides in September, although probably lower mileage than usual. Haven't experienced any further general - black-outs?, although I had headlamp and tailight failure at the beginning of a late afternoon ride around Lake Memphremagog.

I turned back from that ride and back at the shop I found a loose terminal on the light switch in the headlight shell.

I've been taking tools to remove tank and hot wire between battery and Pazon.

August 26, 2014

Installed new battery. 63,300 miles.

Purchased through Amazon.

August 21, 2014

Oil change, 63,120 miles (crankcase, filter, primary chain case)

August 19, 2014

Spent several days tracing and diagramming the wiring and cleaning up connections.

Provoked electrical system 'blackouts' several times in the shop and found two things that sometimes make power return:

1) Playing around with the wires on the switch, as I did on the road on 14 August (below), and also one other time, either in the shop or on the road.

2) Grasping the harness where it comes out from the gas tank and crosses the neck and gently tugging forward and upward. This corrected the electrical fault twice.

So probably a strained connection that is open, but makes contact when tension is removed or reduced. Probably in the headlamp shell.

I no longer think that the ignition switch could be the problem.

I've already looked at looms (about $160 for Bonnie) but I think my best bet would be to make my own since the layout of the components in Bonnie?s electrical system does not match any Triumph factory model (i.e. position of ignition switch and zener diode).

August 16, 2014

Early in the morning. Still no electrics.

Rigged two jumpers to an idiot light bulb and probed around:

But later, after (?)

Fiddling with wires to switch, wires in shell, and wires on rectifier (or did I notice that the center rectifier wire looks funky after the lights came back on - I think so)

Oh, probably the lights came back on after I also tried to push back the Lucar cover on one of the leads, the one that looks burnt at the top.

Also made and unmade the wiring to the speedo/tach lights (only one working) and the idiot lights (one corroded right in, took it out with pliers).

Anyway, at one point I have lights and ignition. I saddle up with every tool and material I need to cure another electrical outage and prepare to go out the door and it starts raining.

August 15, 2014

Wanting to go for a spin and warm up for oil change.

Bike won't start. No ignition, no lights.

Looking around, find that mechanic Dave didn't connect the ground lead to the zener diode when he re-did the ground connection.

Reconnected the zener. No change.

Took various voltage and resistance readings. Measuring from ground to feed side of ignition switch:

Left charger on battery over night.

August 14, 2014

I take a leisurely one hour ride and on top of Nelson Hill I stop to look at the Panorama for a good five minutes.

Comes time to leave. Bike won't start.

Pulled white and white/brown wires off ignition switch and put (white?) onto the second terminal with brown/white. Bike starts right up.

August 12, 2014

Bike won't start in NBE's parking lot.

Mechanic fixes loose ground, puts wire straight to Pazon (with switch) and I ride home, one-hundred dollars poorer.

Engine runs with the switch on and the lights work with the ignition switch on and the lighting switch turned on.

Mechanic Dave's recommendation for electrical supplies:


http://www.britishwiring.com/Ratcheting-Crimping-Tool-for- Terminals-p/pr4.htm

August 8, 2014

Received new ignition switch AND new tumbler.

Installed new switch with OLD tumbler. Everything hunky- dory. Runs great.

Fiddled with timing - retarding it slightly.

August 5, 2014

Electrical problem. No ignition.

Wired from battery directly to Pazon white and she started right up.

Bypassed the ignition switch (plugged all 3 Lucars into a brass multiple) and she started right up.

Ordered new switch.

July 24, 2014

Having lots of trouble getting carbs adjusted for idle. Idle is erratic, (mostly) very fast, and has gigantic 'dead spot' that kills motor every time if I slowly roll through it.

Motor dies randomly in traffic. Real drag.

Runs fine 'at speed'.

I need to mark my throttle handle 1/8, 1/4, 1/2, etc. to help locate faulty carb component(s):

July 10, 2014

Oil change 61,100

June 6, 2014 Friday

New Adjusters Tops!

Before leaving for Magog SAAQ I readjusted valve clearances. The new allen head adjusters are so much easier than the original square locking screws. The allen wrench makes it easy guage adjustments while loosening or tightening the lock nuts with a Whitworth boxend wrench.

Got my new registration at the SAAQ at the same cost as last year - $469. That's with the discount of later registration.

Returning to the Bonnie Castle, I felt inspired to finally fix the broken brakelight wire. Lots of fun fishing around and removing the wire cover on the inside of the rear fender.

Good to have working tailight and brakelights though.

June 5, 2014

Beginning of Season 2014

Bike back on the road after a couple of weeks intensive efforts. Lots of issues experienced this spring.

The Bad & The Good

The Bad

The Good

June 5, 2014 Thursday

Initial run-in

Gasket Compression

Even though I set the valve clearances wider than spec, the valves were getting tight after several minutes of running.

I checked torque on headbolts. Will let the engine cool off until this afternoon and readjust the valves.

June 5, 2014 Thursday

Valve Adjustments

Re-set valve clearances, about a thou over spec for intake and exhaust. Will readjust tomorrow if necessary for .002 and .004".

June 4, 2014 Wednesday

Winter Service & Repairs

June 3, 2014 Tuesday

Cables/Gas tank

May 31, 2014 Saturday

Rear wheel/brakes


Center those shoes!

And the rear brake works great - gone is the "pulsing" effect when braking.

May 30, 2014

May 29, 2014

May 27, 2014 Tuesday

Assembly Continues

May 2014 Replaced front and rear wheel bearings with sealed units from MAPCycle 59,518 miles.

Metal Bits

Draining the crankcase oil I found the metal bits missing from the two intake tappets I replaced.

I gave the crankcase and oil reservoir screen filters a careful cleaning, installed a new oil filter, and topped up the oil.

Before refilling the oil I replaced the inside oil line - it was chaffed from rubbing on the frame (center stand I think) and I had one already measured and cut from the last time. Replacement was 3/16 short of ideal length, but should be ok.

Also refilled fork oil and drained and replaced gear box oil.


Have finally discovered a quick, easy, and pretty greaseless way to thread the chain back onto the top of the rear sprocket: use a chopstick! Pass the chopstick through the spokes and insert the tapered end into the empty hole at the end of the chain. Makes chain on a stick, and easy to manipulate into place without ever touching it.

May 18, 2014 Sunday

Assembled steering head/front forks

May 17, 2014 Saturday

Assembled front/back axles

May 8, 2014 Thursday

Disassembled cylinder block

April 26, 2014 Saturday

Disassembled front axle 1-1/2 hours

April 25, 2014 Friday

Parts Order

Placed a third order with MAPCycle.

Washed up triple tree and brake back plate to make them more presentable when I take them for powder coating in Magog.

April 25, 2014 Friday

1:30 Disassembled front forks

April 24, 2014 Thursday

Rocker Boxes 3 hours

Interesting Discovery

Pulling out the rocker spindles I discovered that I didn't even fit the intake spindle with an o'ring the last time I put it together. Back to Triumph Mechanic School for me! I even kinda remember being so pleased about how easily one of the spindles went in at the time. Moles are cool people, but I should really get some glasses.

But here's something else interesting. The intake spindle with no o'ring didn't leak oil. The exhaust spindle (with o'ring) was the leaking one!

April 23, 2014 Wednesday

Brakes 4 hours

April 22, 2014 Tuesday

Cleaning & Wrenching 4 hours

April 20, 2014 Sunday

Cleanup & Prop 2 hours

April 17, 2014 Thursday

Disassembly & Cleaning 6 hours

April 11, 2014 Friday

MAP Parts Order #2

Ordered wheel bearings (4), fork oil seals, speedo gearbox, and rocker spindle o'rings.

Tip!Retro Note: This Taiwenese speedo gearbox repro from MAPCyle lasted just under 5 years as it "exploded" into pieces in late summer, 2019.

April 9, 2014 Wednesday

Begin Tearing-Down 2 hours

Winter 2014

End of Season 2013

October 22, 2013

59,518.7 (interval: 1,477 miles)

Changed crankcase/primary oil/filter

October 11, 2013

Found the source of all the mess on the tinwork behind the left hand carb, and also the constant smell of gas I've had for the past 1,000 miles, and the really crappy performance for the last 24 hours:

Float in left hand carb was full of gas. Put in one from the old carbs and the Bonnie's very happy again.

Also checked the ignition timing and found both cylinders spot on.

October 1, 2013

On trip with Bob B. to White Mountains, the speedo died. Or at least the speed indicator. The odometers seem to be still operational. Tach is also looking pretty sketchy.

September 22, 2013

58,041 miles

Changed crankcase/primary oil/filter

September 19, 2013

L'Amis Denis couldn't get a new rear tire for Bonnie until mid-October so I had them mount an old, less-worn out one from my shop.

After I returned home and re-installed the tire, including alignment, L'Amis Denis called to say their mechanic had left out a bushing. So, back to Lennoxville and another wheel removal and installation. Mechanic kind of acted like it was my fault he left the bushing out.

Disaster. The second time I didn't correctly install clip on master link and chain flew off on Vallieres, ruining the new Reynolds chain and sacking the chain guard.

August 22, 2013

56,700 miles

Changed crankcase/primary oil/filter (interval 1,200 miles)

Shell Rotella T 10W-40 diesel oil in crankcase. $28 US a gallon inc. Vt tax.

August 21, 2013

56,000 miles

Push rod tubes have been leaking more and more, so I bit the bullet and started wrenching.

Removed rocker boxes and head and replaced push rod tube oil seals (except for bottom exhaust o-ring and seal because the wedding band was really tight and that joint didn't seem to be leaking).

I'd used a red high-temp o-ring at top of exhaust and it was totally deteriorated, coming out in little pieces. Other two o- rings on intake tube were flat, but integral.

All replacement o-rings I used were black ones.

Had trouble tightening domed nuts on rocker spindles because they kept turning, especially the intake spindle. Finally used contact cement (household goop) between spindle head on drive side and screw of a wood vise - with other end of clamp blocked off rocker box fins with small piece of plywood. This gave just enough friction to tighten the nut sufficiently that it didn't leak.

Re-torqued head bolts after about 6 miles and re-set valve clearance. Drove 82 miles (around Lake Memphremagog) and re- checked bolts, which were ok. All four valves had zero clearance.

Also checked timing - ever so slightly retarded in both cylinders, a little more on timing side.

When putting carbs back on I used PL's method - slack idle screws right out - adjust cables for slides being all the way down and synchronized. Then set idle with idle screws.

Bike is very responsive and smooth to throttle control and idles very nicely at 600.

August 3, 2013

56,033 miles

Repaired wiring to center lug of selenium rectifier. I recently used a side-by-side two-to-one connector to connect the brown/white and (other) wires to center lug. The rectifier got loose and turned evidently, shorting to the fender. The resulting heat burned my under-the-seat rags and the blue tool- kit pouch. Totally charred. Lucky I didn't have a fire.

Very thorough ignition timing job pays off. Did static timing first. Forgot to advance the autoadvance with screwdriver, but it all worked out ok when I made adjustments using the strobe. Used an old lawn tractor 12v battery as external power source for strobe - timing mark seemed to jump around a little less.

Timing is right on the spot now and Bonnie is quieter with less vibration, and has more power and smoother acceleration.

Adjusted drive chain.

July 23, 2013

55,500 miles

Oil change with filter. (interval 1,223 miles)

Replaced gaiters.

July 10, 2013

54,717.7 miles

Changed crankcase/primary oil/filter

New primary chain adjusted

New fork oil

Reset timing for timing side cylinder (it was retarded). Went really well using my points photo as a guide

June 28, 2013

Oil and filter at 54,277 miles

Beginning of Season 2013

June 3, 2013

53,310 miles

Started first kick.

Overheated on way back from Ayer's Cliff, but after re- adjusting valve clearance everything's been fine.

Bike's much quieter without rattle from loose chain guard. Handles better with new shocks and adjustment of steering head races (loose all last year).

No oil or gas leaks!

Winter Tear-Down 2013

May 22, 2013

End of Season 2012

October 2012

End of 2012 Season at 53,310 miles

5,460 miles during 2012 season.

October 22, 2012

Oil change . 53,100 miles

October2, 2012

Oil change. 51,800 miles

September 5, 2012

Oil change. 51,040 miles

Found ignition coils loose (again!)

September 12, 2012

50,680 miles.

New K70 rear tire mounted by L'Amis Denis

August 23, 2012

50,300 miles.

New drive chain installed and adjusted.

Changed center stand spring and replaced nuts, bolts, tab washers holding the stand to frame. Replacement bolts don't thread into the threaded holes of center stand the way the originals do, but they seem to do the trick.

The method I finally used to get the new spring on works really well ? no strain! Fold about a 6? section of 1/4" nylon rope and pass the folded end from front to back over the frame member where the spring anchors. Hook the spring over the loop and then pull the spring on from the front with one foot on the drive side footpeg for a brace. After the spring is on, pull the rope out the back way.

Installed new parts for the steering damper.

August 2, 2012

49,400 miles

Oil change.

Pre-Ormstown check-over found about 8 bolts or nuts loose to some degree.

July 12, 2012

48,607 miles

Beginning of Season 2012

July 6, 2012

47,550 miles

Midseason Service & Repairs (ascending chronological order)

  • Top end re-assembled w original order of washers (July 5th)
  • Top end assembly w alternate order of washers on rocker spindle
  • Snapped rocker box bolt removed (Jamie Bruins)
  • Valves lapped lightly (Jamie Bruines)
  • Sandblasting head (end of May)

    Winter Tear-Down 2012

    January 9, 2012

    Slacked off valve adjustments and loosened all head bolts to hand-tight.

    Found bolt missing from forward head-steadies. That's the bolt I found at Crooks car wash just before the end of the season!

    Also found rocker box and head bolts not very tight - perhaps 2 were not much more than hand tight.

    January 8, 2012

    Removed gas tank, carbs, head steadies.

    End of Season 2011

    47,550 miles end of season.

    September 28, 2011

    47,550 miles

    Oil change: crankcase and primary chain case.

    Replaced cracked headlight lense with new Lucas ($55).

    August 27, 2011

    46,700 miles

    Oil change: crankcase and primary chain case.

    August 18, 2011

    Been hearing a noise over the past week - kind of a rattle, or sound of a wind-up clock's spring suddenly releasing. Hearing this mostly at a stop at idle as rev's decrease.

    This morning I tore down the transmission completely, removing the engine and clutch sprockets. Found nothing loose except for the primary chain being quite slack.

    Those econo chains from BSC really stretch a lot!!

    Put everything back together (3 1/2 hours to tear down transmission and re-assemble) and put more tension on the clutch springs.

    Went out for a two-hour road test - the noise seems to be gone and the clutch no longer is slipping - what a difference in acceleration!

    I did notice that the left-hand ends of the rocker spindle's are moving around a bit. Checked the dome nuts at the other end and they seem quite tight. Maybe this is normal, I'm not sure. Or maybe I have too little clearance for the valves? Doesn't seem so though.

    August 10, 2011

    46,200 miles

    New spark plugs - Autolite N3 equivelent (but copper)

    Checked points - left them alone

    Re-set timing (right cylinder was out a little)

    Valve adjustment using this method:

    July 26, 2011

    Oil change: 45,315 miles

    July 5, 2011

    Oil change: 45,075 miles

    June 22, 2011

    Installed new rear tire: 44,730 miles

    June 8, 2011

    44,250 miles

    Changed crankcase/primary oil/filter

    Clutch slipping less since I changed oil and used 30W non-D and less (~300 ml)

    June 5, 2011

    Installed replacement oil filter head - no leak!

    May 26, 2011

    Beginning of season issues:

    Ordered new front and rear tires today.

    Start of Season 2011

    April 2011

    Start of season odometer reading: 43,3841 miles

    Winter Tear-Down 2011

    Installed Norton oil filter head


    End of Season 2010

    September 25, 2010

    42,530 miles odometer reading.

    Installed new clutch friction plates. No more slipping clutch.

    Also, checked cylinder compression:

    Cylinder Opposite plug in Opposite plug out
    Left 145 psi 150
    Right 120 psi 150

    September 21, 2010

    42,497 miles

    Changed crankcase/primary oil (485 mile interval)

    September 1, 2010

    42,015 miles

    Changed crankcase/primary oil (1,236 mile interval)

    July 23, 2010

    40,779 miles

    Went through a period of backfiring and missing after initially running quite well. Eventually, after fretting over valves, timing, and carb, I put the battery back in after having replaced it with a capacitor. Bike instantly began running normally again with the battery in the circuit.

    Bike definitely has more power than before the rebuild.

    Had used a bit of oil - about a quart in 500 miles. And the clutch has been slipping occasionally on two of my last three outings.

    Beginning of Season 2010

    July 4, 2010

    Bonnie back on the road

    40,397 miles

    Winter Tear-Down 2010

    June 9, 2010

    Retrieved motor from Costa Zarifi.

    CZ changed (40,397 miles)

    Season 2009 Cancelled

    Winter Tear-Down 2008

    January 6, 2008


    Valve job by Frank Holmes

    End of Season 2007

    Mileage, 2007

    Event Speedo Reading
    Beginning of 2006 season (original speedo) 28675
    Original speedo out of service 31493
    2006 Subtotal (old speedo) 2818
    End 2006 season (new speedo) 2550.1
    2006 Subtotal (new speedo) 2550.1
    2006 Grand Total 5368.1

    November 14, 2007

    Installed new speedo cable but the speedo still doesn't work. Speedo works with electric drill, cable has no "flitches" in it, but output from cable from gearbox is pulsating. Guess I need a new gearbox.

    October 5, 2007

    Oil change (crankcase, chaincase), new rear tire, new chain (Reynolds), and new sprocket.

    Occasion for another new chain being that I cut the first one a link too short.

    July 30, 2007

    37,079 miles

    Changed crankcase/primary oil (cleaned sump filter only)

    Checked points - gaps and timing are right on.

    Adjusted idle screws on carbs.

    New chain (Reynolds) put into service. Aligned rear tire (twice with new chain, once with old).

    Melted down ground leads by shorting out battery (-) with oil dip stick. I should turn battery around so terminals are further away. Put insulated booties on?

    Removed front brake lever assembly (from Waldridge I'm pretty sure) due to cracked and broken screw mounting. Replaced with - original? Replacement is upside down (cable inserts into lever from bottom and not top).

    July 15, 2007

    36,630 miles

    Replaced front wheel bearings.

    June 23, 2007

    Changed crankcase/primary oil (no filters cleaned)

    Lubed points fluffs and cables.

    May 28, 2007

    34,979.2 miles

    Changed crankcase/primary oil (cleaned sump filter)

    May 25, 2007

    Lost left muffler returning from East Hereford.

    May 10, 2007

    Lower mounting bracket on chain guard broke weld to chain guard. Brazed by welder in Magog.

    May 03, 2007

    Left front mounting stud on gas tank broke off. Repaired by Atelier des Profs with their brand of liquid steel.

    Beginning of Season 2007

    March 22, 2007

    33,750 new miles (18,000 miles total).

    Maiden voyage to Ayer's Cliff and then around lake Memphremagog. Sixty-eight miles in all. Issues:

    Winter Tear-Down 2007

    March 20, 2007

    Front forks work:

    Lower leg replacement from Hutchinson had a different type of drain plug (elongated tip - for sediment?) and also had threads in the mounting lug for the rear front fender stay.

    I also ordered a new dust cover but it was not a good match with the other original so I put back the original one. I did note that the new dust cover threaded on quite snugly while the old one threaded on fairly loosely until the last little bit.

    When I took apart the forks I found that the circlip had come off of the shuttle valve on both sides. One of the check valves is a bit beat up but I put it back in because replacement was not immediately available.



    Things done/not done

    January 28, 2007

    Have stripped Bonnie down to engine in frame, fenders, front end, front tire, oil bottle.

    Issues/things to do:

    End of Season 2006

    2006 Issues

    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!

    December 25, 2006

    Event Speedo Reading
    Beginning of 2006 season (original speedo) 28675
    Original speedo out of service 31493
    2006 Subtotal (old speedo) 2818
    End 2006 season (new speedo) 2550.1
    2006 Subtotal (new speedo) 2550.1
    2006 Grand Total 5368.1

    November 24, 2006

    33,629 miles

    (interval 929 miles)

    Crankcase: Quick Change (filters not removed, sump not drained)

    October 14, 2006

    32,700 miles

    Changed crankcase/primary oil

    September 16, 2006

    31,884 miles

    Rear tire flat.

    Installed new K-70 tire and tube (D'eauville)

    September 10, 2006

    31,700 miles (new speedo)

    Changed crankcase/primary oil

    Cleaned and lubed chain

    Also, installed new cables for carbs and clutch and adjusted timing and idle. Bike is running like new!

    September 7, 2006

    Replace speedometer with a rebuilt from Frank. Old speedometer stopped at 31, 493 miles (see table above).

    September 1, 2006

    Bonnie popped out of 4th gear yesterday and left me in neutral with no gear changing action from the foot shift (no clicks, just up and down).

    Coasted back to Dave's driveway where foot shift still didn't work, but then it started working about five minutes later. Went on to ride for several hours with no problems.

    I was cranking pretty hard going up the hill at 70 when she popped out.

    August 25, 2006


    Changed crankcase/primary oil

    Before leaving on trip down to NH to meet Richard Swartwout

    Stopped at Frank Holmes Brit Bike Barn, former home of Bonnie. Frank was effusive in praise of the bike. When he heard about the top end job and subsequent oil burning he ran into the shop and came out with spark plug wrench and compression test in hand.

    Both cylinders measured between 165-170 after 5 or 6 kicks.

    After the rebuilt they measured around 135, but I didn't hold the throttle wide open the way Frank said to.

    August 12, 2006

    After a spate of headlamp bulbs breaking I solved the problem by putting a small dab of grease on both contacts of the last bulb I put in. The contact assembly twists on quite stiffly and evidently without the grease it had been stressing the bulbs base with respect to the glass, resulting in breakage in quick time.

    July 30, 2006

    Replaced exhaust pipes after striking rock in the wake of a road grader.

    I asked for 'skinny' pipes this time instead of the 'fat' pipes I got last time from Don Hutchinson. The first set had a bad bend in the right-hand side pipe and I had to return them for a second pair.

    I'm not totally happy with this set either - they go on but I think the angles between the pipes and the jugs are not completely right - I have a hard time sealing the exhaust gasses in at that joint.

    Beginning of Season 2006

    28,675 miles.

    Winter Tear-Down 2006

    March 15, 2006

    Completing winter 2005/2006 maintenance at 28,675 miles

    Compression after rebuild: 135/135.

    Top end rebuild, including:


    Gas tank

    Oil tank

    Frame and most brackets and tin





    Pre-rebuild top-end spec's (Patrick Degens') at 28,675 miles:



    Measured Specs Action taken
    Valve stems inlet .3082 & .3082 .3095-.3100" Changed
    Valve stems exh .3075 & .3097 .3090-.3095" Changed
    Valve guides inlet .3129 &.3132 .3127-.3137 Kept
    Valve guides exh .3129 & .3128 .3127-.3137 Kept
    Tappets inlet .3100 & .3110 .3110-.3115 Changed 1
    Tappets exh .3110 & .3115 .3110-.3115 Kept
    Piston clearance .0062 & .0062 .0046-.0061 Kept
    Rings (all ) .018 to .025" .010-.014" Gap Changed
    Cylinder bore (+.020) 2.8152 & 2.8151" 2.8148-2.8153 No rebore

    Note: the following part numbers reflect the sealing condition found from '70 until '73, to which Bonnie was evidently upgraded previously.

    Part Number Part Description
    E-7310 bottom pushrod tower sealing o'ring
    E1-1283 top pushrod tower sealing o'ring
    E-4752 sealing ring (white, square-edged ring)
    E1-1707 sleeve (aka wedding band!)
    E1-2575 correct push rod tower number

    January 14, 2006

    Picked up powder coated frame, brackets, and tin.

    End of Season 2005

    December 8, 2005

    28,675 miles

    Last ride on 1 December.

    Tearing bike down for winter maintenance.

    September 23, 2005

    Received replacement left-hand carb and it works just fine.

    Now that both carbs will tickle, Bonnie starts right up on two cylinders again.

    September 8, 2005

    Installed new Amal concentrics.

    A few issues: 1) left carb won't tickle (just like old right carb) and 2) can't properly thread air cleaner onto the left carb.

    Idle screws are right out giving no idle unless throttle is held open at the twist-grip - however, it started on about the third or fourth kick and on a short test run down the hill, and a way past the Stanstead county line it ran very well:

    No coughing and missing as before and pinging has subsided greatly (gone except under stress?). The formerly jerky low and mid-range (2,000-3200rpm) throttle response is now very smooth. I've never been able to come up the hill as slowly and negotiate the first corner with no engine ping.

    Top end? Had no helmet on and only took her up to just under 70 on the winding turns of gravel road. It did seem to have a bit of a dead spot up there, but hard to tell.


    Replaced front stay. New one broke in less than two hundred miles.

    May 7, 2005

    23,750 miles

    Beginning of Season 2005

    April 14, 2005

    23,045 miles

    Winter Tear-Down 2005

    Began readying Bonnie just about a week ago. Had a new rear tire mounted and replaced the wheel with lubed chain.

    Then I checked the valves - exhaust seemed ok, but the inlet valves seemed to have no clearance at all so I readjusted them.

    Reassembled everything and gave her a kick outside - started right up on the first kick, but only on the left-hand cylinder.

    Spent four days working on the electrics because the right- hand cylinder's spark looked weak to me - ordered new coils from Moto Montreal and they arrived next day by express mail but they were the wrong ones so I drove to Montreal and exchanged them.

    After reassembling with new coils she was still hitting on only one cylinder so I pinged the BritIron mailing list. Pete Chartrand was first to respond and he was right on when he said to check the two small holes in the needle jet. Passed a slender wire through them, reassembled once again and Bonnie roared to life on both cylinders on the first kick.

    Took a short spin down to AC and back and then took a ride to Magog today after first going to Crook's car wash in the village. It was about 5 degrees C but I had on two pairs of pants and my riding jacket with winter liner so I was very comfy.

    End of Season 2004

    October 29, 2004

    23,045 miles

    Changed crankcase/primary oil (1,200 mile interval)

    Cleaned and lubed drive chain(530 mile interval).

    October 26, 2004

    22,980 miles

    Dip switch died this week - shorts out battery and blows fuse on high beam.

    October 10, 2004

    22,516 miles

    Chain cleaned and lubed

    New chain's master link came off very easily using a small drift to punch the connecting link out of the cover piece. Used the needle nose vice grips to put the cover piece back on far enough when replacing and I think it went a bit easer than the first time, but still very thight.

    While checking tire alignment after replacing chain I noticed that the rear tire is practically finished - just a tad better than when I replaced it on July 23 at 21,100. That gives me 1,400 miles on the tire - can the gravel be that hard on tires? I think something?s wrong here. I?m estimating that the last tire (put on by Frank) lasted in the vicinity of 7,000 miles.

    Also noticed yesterday that all Bonnie?s lighting was out. Thought it?d be a connection on the lighting switch but instead it was the feed to the lighting switch from the ignition (brown/white wire on ignition switch connection the farthest forward).

    September 25, 2004

    21,845 miles

    Changed crankcase/primary oil (1,259 mile interval - oil was quite dirty)

    September 4, 2004

    21,108 miles: chain cleaning and lube.

    September 2, 2004

    Replaced metal cover on drive side which I lost several days earlier on a ride around the west side of Lake Memphremagog in Vermont.

    August 13, 2004

    20,568 miles

    Changed crankcase/primary oil (833 mile interval)

    Cleaned and lubed drive chain.

    August 10, 2004

    Adjusted the ignition timing using a stroboscope. Hard to see but then I marked it with black magic marker and waited until dark (bike was outside).

    Also managed to turn both headers yellow (even some purple on the drive side) - 2,000 rpm while stationary is enough to overheat the bike.

    Once I could see the timing mark under the strobe it only took four or five seconds to check a setting. I think trial and error is best because my arms aren't eight feet long. It would be good to note adjustments in terms of advance and retard for future reference.

    July 23, 2004

    20,100 miles

    New rear tire and tube.

    July 14, 2004

    19,911 miles.

    Cleaned and lubed chain

    July 12, 2004

    19,825 miles

    Changed crankcase/primary oil (1,060 miles interval).

    Also installed new oil hoses between oil tank and oil pump junction block. New hose is softer, more pliable than the old. New clamps seem to tighten it right down and there is no longer any leakage from the oil pump side connections where there definitely was before. There still, however, seems to be some oil leaking from somewhere.

    July 6, 2004

    Since 'completing' restoration reassembly I have lost, or nearly lost:

    June 14, 2004

    Lost a chain in Rock Island. Evidently I didn't snap on the master link clip after replacing fresh chain. Had none to fit at home, got towed home by Dodge dealer. Picked up new link next day at Moto Montreal.

    June 11, 2004

    19,400 miles

    lubed chain (medium chain bar oil overnight and drain).

    Beginning of Season 2004

    May 26, 2004

    18,765 miles

    First ride of the season.

    Winter Tear-Down 2004

    Did a lot of maintenance this winter, but details are missing - notes say "see separate document".

    Changed crankcase/primary oil

    Changed gearbox oil

    End of Season 2003

    2003 Issues

    November 25, 2003

    Mileage: 18,764.

    Last ride of the season.

    October 12, 2003

    18, 200 miles.

    Changed crankcase/primary oil (inc. filters)

    Failed to tighten primary oil level screw, evidently, and lost it on first 30-mile ride. Doesn't seem to be any damage to chains or clutch, though. Found a screw with thread close enough (might be a tad loose in the thread) for a temporary replacement.

    Aligned rear wheel using a straight-edge (1 x 4 pine) but was way off. As soon as I rode (same ride as above), I could feel the bike tracking to the left and acting weird. Re-aligned using instead a piece of mason line - much better!

    September 26, 2003

    Went to Moto Montreal. Talked with Chris. New concentric carbs are $200 apiece. A damper would run about $60 in parts.

    Picked up headlight and speedo bulbs (bayonets) as well as a set of new footpeg rubbers.

    August 30 , 2003

    Oil change 17,150 miles. Includes primary chain case and crankcase. Washed all filters in kerosene.

    Adjusted clutch - just right now at a little under a half turn out from plate lift. Doesn't seem to be slipping now, but gear changing is smoother. Noticed today that going very slow and easy from neutral to first at a standstill seems to go quite easily.

    August 29, 2003

    Thought I had tracked down the dead RH cylinder problem to a bad condenser (points for RH side seemed to be arching - a faulty condenser according to Haynes), but after replacing both condensers ($36 plus tax from Moto Montreal) the problem persisted.

    I went over everything again - hooked up the ignition switch correctly, etc. Finally switched plug wires and watched the problem move from Right to Left cylinder as I turned over the engine with plugs out and grounded, watching for spark.

    Got two new wires made up by Magog Auto Elentrics (Sherbrooke street) and Bonnie started right up on two cylinders.

    Meanwhile I have removed the ugly bracket that held the horn and the condensers and mounted the condensers directly to the frame there instead of to the bracket. Of course I also removed the horn relay and all the extra baggage wiring.

    Starting to look a bit cleaner.

    Couldn't go for a ride afterwards due to rain, so I cleaned the air filters instead.

    August 27, 2003

    Well, I may have fixed the intermittent ignition switch problem, but now the right-hand cylinder is completely missing at low revs. I went out twice since cleaning up the switch corrosion and the problem gradually got worse and worse to the point that the r-hand cylinder hardly fires at all until rpm's are way up and even there it bogs.

    Yesterday I could see that the spark on that cylinder is very weak. I cleaned the plugs and points and checked all gaps - .020 plugs, .015 points (they were both very tight, plugs were a nice light chocolate brown).

    I also checked the ignition switch - I think it's connected correctly, but I'm not 100 percent sure.

    I pulled off the tank again today and looked at all the coil connections that I re-did the other day before discovering the corroded ignition switch. Everything looks ok.

    Could be capacitor or coil? Wire? The spark was weak from plug end of plug wire to ground with the bike running (on left- hand cylinder).

    Tomorrow I need to check origins of the brown/white and white/brown wires to ignition switch with VOM to see if the ignition switch is truly hooked up properly:

    I'd swear that before I played with the ignition switch the first time (below), the lights would not come on until the ignition switch was turned on, whereas now the lights will remain on after the ignition switch is turned off.

    August 24, 2003

    Bike was stalling two nights ago when LA and I went for a ride to Magog and North Hatley and today it died completely when I got to the bottom of our hill.

    I found the problem - bad contacts (corrosion) on the ignition switch. Cleaned them up and its working fine - this should also fix the anomaly that I noticed when I drove to Sherbrooke the first time this summer- bike stalling when making a left-turn from a light. This was because turning the front wheel to the left moved the big plastic-covered part of the wiring harness that goes up to the headlamp shell and that was what was making the ignition switch contact intermittent.

    August 1, 2003

    16,500 miles

    Changed crankcase/primary oil

    Tried adjusting the clutch again - to about 2/3 of a turn, clutch still drags.

    21 July, 2003

    Clutch was slipping. Manual says to back 1 turn off of where plate lifts, bike was adjusted right to where the plate lifts. I backed it off one turn and the clutch is now dragging a bit too much - gear changes are a bit chattery.

    Start my Bonnie log

    June 28, 2003

    15, 768 miles.

    End previous owner log

    May 23, 2003

    (Last entry by Frank)

    New fork seals and gators.

    August 12, 2002

    Re torqued head, set valves, changed gear oil.

    August 10, 2002

    190cc 30w oil in front forks.

    August 8, 2002

    New front tire and new front fork gator.

    De glazed front brake drum.

    July 8, 2002

    New 20" (or 15 thousandths inch) over pistons and new valve guides.

    June 23, 2002

    New K70 rear tire.

    New rear brake shoes.

    New center stand spring.

    Adjusted primary chain.

    June 22, 2002

    (Start for Frank)


    Disassemble carbs, replace needle jets, check floats, clean airways.

    No sign of oil leakage past guides.

    # 3 slides

    # 190 mains

    Rear speedometer drive: [3 or B]65330/168

    Rotor: 15/12 =1.25-1

    About The Bonnie Ref

    "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)

    About Bonnie

    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.

    Beginning of log: T120R Engine & Frame NC00125

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