yes the bore is two sizes over i believe stock is 89 mm and it was 89.5 untill i put a 90mm piston in. also i have not rejetted it yet, i moved the clip on the needle 2 spaces richer, and did not want to adjust the main jet untill it was fully broke in and i could hold wide open throttle to look at the plug. I will probabally put a larger main jet in now, but i am worried that damage is happening. it dosent feel like it, and it runs great otherwise. has any body else ever had this happen, or can explain why the motor would temperally seize. my plan is new plug, sythetic oil change, bigger main jet, and ride it, but i am kind of scared to damage the motor, and cannot afford another rebuild.