Ok, well i'll start with when i first got this blaster it bogged at the low end of about every gear and didnt have great compression so i did a top end rebuild. Took it to yamaha and they bored it (found out later it was on the last bore which i believe is .90 over) and they ordered my piston kit, gaskets, etc. Me and a buddy who has 2 blasters put it back together and rode it a little to break it in. The next week we go riding and we ride for 20-30 minutes and my blaster cuts off in the middle of 3rd gear. Wont crank back up, the kickstart locks up sometimes but then breaks loose, then it wont have good compression. So we take it apart and the piston has had one top side shaved off a little. What in the hell caused this? I was running a 310 mian jet with airbox lid off and a full pro circuit exhaust. Everything else is stock motor wise.