I am currently the parts manager at a Polaris shop. The mechanic, a local performance engine builder and myself have noted the obvious problem the 500's have with their exhaust lobes on the cams. We believe it is caused by the decompression ball. If any one has taken their head off and looked at the exhaust rocker you will notice wear and chipping. We have noticed this as early as 400 miles (my machine when we ported it). Our mechanic, who is known by the techs at the factory by name(for good reasons), asked if they too believe this is caused by the decompression ball in the cam. They stated that it had something to do with it however they do not believe it is the cause of it. They are standing behind them firmly though, we have warrantied ones as old as '98. So you other 500 riders don't have a stroke! My question is, has anyone tried to grind any surface away from the release lever (part#3085348, Ref#16, on D6 in the HO microfiche) so it releaves some of the stress off the rocker? And if you have how far can you go (in thousandths) before it makes the motor too hard to turn over? If not we will be trying it this fall when we do a more extreme port job, stuff a high compression piston and long duration cam in it. So we will let you know if this has crossed any other piston head's mind.