OK my buddy has a 06' RM125. He just had the cylinder replated, they matched up a wiseco piston for it, 2 hours on it and it siezes up, once it cooled down it released the piston. This guy has rebuilt 100's of two stroke motors. After tear down the piston crown had severe pitting and scoring on four points of the piston at equal points like an X. The ring was stuck like chuck. so he replaced the piston with the same piston, started right up, he did 4 15 minute heat cycles with no problem. his kid rides it easy for 15 minutes, brings it back lets it cool, X 3. 4th time it locks up again. after tear down, which I assisted in, the piston was scored on the front, and the ring as stuck again, there was also shrapnel of an undermined source, embedded in the crown and cylinder head. after further inspection we found the big end bearing was toast, and are assuming the shrapnel came from it. So we are going to rebuild it again from the bottom up and I'm wondering what piston you guys recommend, we would like to find a twin ring piston, but it looks as if that is not an option for this model. Any suggestions would be appreciated as we are both YAmaha and Kawi guys.