I rebuilt my clutch assembly three times now. Every hundred miles or so after my rebuild (all proper torque's etc.) the splines on the stationary sheave of my primary clutch has the splines completely shaved off. The clutch than really becomes stationary and the belt burns and coats all of the secondary clutch and my JBS primary sheave. I believe that I have finally noted the cause of this expensive problem. The spines on my primary wet clutch shaft are worn down considerably, causing all of the weight and pressure to be on the weak ends of the primary stationary sheave spines, breaking them off and then the self eating watermelon syndrome comes into play. Has anyone heard of this problem before. Apparently this spine deficiency was already on the machine when I bought it used from a Yamaha Dealer. How involved is it to just replace the wet clutch shaft and housing assembly. I have already plugged the wet clutch and would like to just move the parts over to the new shaft/housing assembly. Any thoughts from anyone. Also, do I have to remove all of the burnt rubber off of the sheave's? (and how is that done). It is getting expensive buying new sheaves every hundred miles, but it does keep JBS in business.