CR500 dirtbike question

Generally a kickstart will have a gear that rides on the kickstart shaft and it is spring loaded. When the kickstart is kicked, it gets cammed down to engage with the gear on the clutch basket. This, of course, is generalization and you'll need to take that sucker apart to find the true cause of the problem. It could be the gear itself, the camming mechanism to a busted spring boss which would entail a new case. You will need a new gasket and it never hurts to change out the seal if you have it apart already anyway.

BTW, those are bad *** bikes. Explosive power. :)