1969 Triumph T120R 650 Motorcycle

Gearbox Components

Reference Photos

(Click thumbnails in left-hand scrolling menu to display large images)

Gearbox Reference Photos

Here are clear, detailed photos of the gearbox parts of a 1969 T120R Triumph Bonneville.

We begin with photos of old and new mainshafts, camplates and plungers, where we see wear and subsequent changes in form. Next there are photos of the gears, in and out of the gearbox, and as a free-standing cluster. Couple of transmission parts (clutch) snuck in here somehow, and finally there's the assembly order of the kickstart ratchet parts inside the gearbox outer cover and the lineup of fasteners for the outer cover.

Pay no attention to the Pazon photos.

Hermit's Triumph Unit 650 Gearbox Articles and Illustrations

Disclaimer: I am not a gearbox guru. However, I have collected a lot of info, and a lot of photos and illustrations about Triumph unit 650 gearboxes, as well as links to many valuable resources, and placed it all at your fingertips right here.

The Bonnie Ref: A Hyperlink Junkie's Field Guide to the Bonnie: Gearbox

This is the Gearbox chapter of "The Bonnie Ref". It's loaded with info on tearing down, inspecting, and reassembling the gearbox parts, complete with descriptions, diagrams, specs and more, with links to pertinent factory bulletins, forum discussions, and other sources.

Triumph 650 Gearbox in Photos and Photo Animation (Front View).

These photos show you exactly how the camplate and gears move in all the gears, either in stills or as a unique animation of the Triumph 650 gearbox.

Triumph 650 Gearbox in Photos and Photo Animation (Rear View).

The same great gearbox photos and photo animation but viewed from the rear.

Triumph Gearbox Assembly Methods Comparison

There are many ways to put a Triumph 650 gearbox back together. Here's a side-by-side comparison of the methods described by the Triumph workshop manual, the Haynes workshop manual, and, the master himself, Hughie Hancox:

Hancox Gearbox Assembly Method

Here's a step-by-step description with photo illustrations of the clever way Hughie Hancox stuffs a Triumph unit 650 gearbox. It just can't get any easier than this! I'm laughing the whole time I'm doing it this way - how can it be so easy!

Camplate & Quadrant Indexing

Having trouble indexing your Triumph unit 650 gearbox's camplate and quadrant? These photos and descriptions will make indexing a snap, whether it be in first gear, fourth gear, or neutral between 2nd & 3rd. Shows you exactly how to position the camplate and the quadrant for whatever method you use.

More Gear Stuff...


Have you seen Hermit's Animated Triumph Gearbox yet? It's pretty cool. Pick your view and take a look!

From back looking forward



From front looking back



Camplate Indexing
Illustrations and photos depicting three different methods to index the camplate and quadrant in a Triumph Unit 650 Gearbox