Bit of advice sought here. Putting together a Comet, slight mods, but nothing much more than standard really 8:1 piston, ported, carb. Just rebuilt an Atlas gearbox for it and now puzzling over primary drive.
Box is set with adjusters as advised in that excellent article by Conrad Osborne, edited by David Dunfrey "fitting an AMC/Norton Gearbox to a Comet".
We have a complete Commando clutch for Triplex chain + mainshaft (fitted to box), Vincent Comet main engine sprocket -single chain, springs and gubbins as per standard.
Choices are as follows as to what happens next:
Box is set with adjusters as advised in that excellent article by Conrad Osborne, edited by David Dunfrey "fitting an AMC/Norton Gearbox to a Comet".
We have a complete Commando clutch for Triplex chain + mainshaft (fitted to box), Vincent Comet main engine sprocket -single chain, springs and gubbins as per standard.
Choices are as follows as to what happens next:
- Fit a Norton beltdrive clutch basket system, fettling an alloy pulley for the Vincent mainshaft at the front, AT10 belt - can just about get a 1.6 tooth ratio, near standard. Problem is that with this there's no cushdrive in either the Commando clutch centre or rear hub, not really enough 'give' if at all in the system -from what I understand belts are tighter than a chain too, short lived gearbox is what I'm sensing, as nice as the Newbie's Clutches are, rather not stretch that far if possible.
- Option two, Ditch the commando clutch, get an old AMC one with cush drive rubbers and run a standard single primary chain.
- or thirdly, one I'm leaning towards financially -forget belt. Use Commando clutch, fit a twin sprocket set up on the crank end with triplex chain -done.