Transmission
This Phase used a standard 4 speed AMC box from the Commando. The kickstart mechanism was removed, allowing simple reversal of the lever for a "right way up" gear change pattern.
Commando
box and clutch. The clutch is heavy both as dead weight and rotating mass, but I
knew I would be abusing the clutch with tall gearing and I wanted
unbreakability.
The Commando clutch action is comparatively heavy so I have eased the profile of the lifting
cam – where it acts on the roller. Don’t touch the working surface at
the Off and Full Lift points, but smoothe out the transition - the section
coloured red in the photo. I have also
removed three of the Commando diaphragm fingers and enlarged the circular
drillings at the base of the fingers, it works without problem but, however, I am not sure
that this was worth it!!
Primary
drive is toothed belt – great!
Due
to Commando gearbox sprocket and rear wheel, I
run the slightly larger Commando chain which does infact just touch the rear lhs
frame loop if not kept at the correct tension. I have covered several thousand
miles and also used to race with a similar set up and have had no frame
problems. With a cush in the Commando Clutch and a cush in the Commando rear
wheel it should be no problem to run a standard, thinner, chain.