after snapping the kick start shaft on a old 93 concept 32 trials bike, im replac ing it with the upgraded 18mm shaft, but it apears to me theres a washer or needle bearing missing where the end of the shaft slots into the casing behind the gear on the inner side of the shaft, is this correct? as there is evidence of grinding against the inside of the casing and the kick start is jammed(not just the compression)when its all re assembled and the outer caser bolted on. any ideas on where to find an online manual or video for this task?

Gas gas Usa have a decent website, though not sure how far back it goes.

Hope this helps.

Gasgas usa website.

Hello rd1,

I never heard of a 16 to 18 mm conversion for the shaft, but I guess that you have been supplied with the later model (I think from 1996) shaft, so I also guess you either have a later clutch case or have accurately bored out your old case and fitted a new 18mm seal, probably the latter as I think the clutch case mounting screw hole positions changed after 93 or so. (It was after the 92 models - have a look to see if your motor is a 92 or 93 model)

I don't recall any thrust washer between the end of the inner shaft, but there is a washer then spring before the inner gear on the shaft, then a sleeve then the outer gear followed by an aluminium washer and the k'start spring.

Have you measured up the 2 shafts to determine if the inner dimensions are the same?

I think the inner end of the shaft runs directly in the casing.

Yoy haven't got too many washer's there have you?

Bye, PeterB.

thanks.when i phoned gas gas they said they couldnt supply me with a 16mm shaft as they only sell the 18mm now. Yeah i got the case re bored to take the bigger seal n shaft.well there was no spare washers, and when it was all put back together again, it seemed locked solid,the clutch moves freely aswell as the piston so its not seized as was another theory as it has been sat idle in a leaky container for a while, an exploded diagram of the assembly might be usefull, but i woulda thought as i had an experienced mechanic doing it with me that we would of put it all back correctly as he helped take it off to satrt with. any other ideas welcome

the new shaft was longer than the old 1 so ive had the inside of the casing machined down where the outer end of the shaft makes contact with it. now the clutch doesnt work the levers all floppy i had the lever wedged so it wouldnt be moved while i was doing the work. i havnt put any oil in the drivetrain yet as im waiting for the liquid gasket to set, would no oil make the clutch not work?