Just broke in my new motor. 4mil long rod crank, Wiseco pistons, trail / dune port, fast head with 21mm domes, adjustable timing plate +4, 34 pk's 152 mains, pro circuits. I broke this motor in real nice and easy. Had at least 5 hours on the motor when this happened. Finally started to get on a little bit, not holding it wide open or anything, but hitting the trail pretty hard. About 10 miles down the trail I locked up a piston. Made a mess of the cylinder. Must have got really hot. was all messed up around the outside of the piston. Thought maybe there was a blocked main jet, they were clean. the other cylinder looks perfect like I just put it in. The top of the cylinders look brand new. It only happened on the one side. The bike really hauled ass until this happened. Would like an idea of how to prevent from happening again. Was thinking maybe of going a few thousandths over on the new bore with a new Wiseco. Any help would be appreciated.