Thunderbolt gearbox

[dbd32]

Can anyone tell me why, when selecting first gear there is a rather big CLUNK   the rest of the gear selections are pretty faultless, up or down
The clutch seams to be set up ok(which has an SRM pressure plate with the needle roller lift mechanism)
What would be worn to cause this

[DAVE BRADY]

Hi,

A few things can cause this clunking.  One is sticking clutch plates.  Even slight sticking can cause this but pulling in the clutch lever and turning the kick start will free this off.  Slight sticking can occur in the best set up clutch so it is worth giving the clutch a turn before starting the engine.  Wear in the clutch can also be a cause as over the years the plates can make grooves on the centre and basket which can cause the plates to try to stay in the grooves and so give a dragging effect making the engagement of the gears a bit rough.  Assuming that it is non of the above then it is most likely that the clutch is not lifting fully square and as there is not a lot of lift on the clutch mechanism, especially the later ones, this can cause a bit of drag.  Even with an SRM pressure plate this can still happen.

Dave.