Hi I'm new here a.d new to this bike . It's a 1999 Kx 80 just bought . The previous owner was going full throttle and the piston broke and messed up the cylinder and port. So he sent out the head and had ignored and the factory sleeve installed with new piston wrist pin and gaskets. So I can get it to file and die out then its like seized up pop it in like 4th gear roll back and forth and frees up. Kick it again fire dies kick it again and like seizes up again. Any ideas what I should check thanks for help Jon.