A while ago i bought a wiseco piston for my bike(99 yz 125). SO i go to instal it every things smoothe and then i go to start it, klank,klank, klank, klank, klinke. i hit the kill switch as fast as i could. this was a loud clanking, VERY VERY BAD SOUNDING. I tore it down about 4 times and double checked every thing and could not firgure out what the problem was. SO i ended up instaling the old piston with a new ring on it. The bottom of the new wiseco pistons has a small indent on the back side of it, so im guessing it was hitting the rod or case? but they both pistons seemd to be the same size. I know that the wiseco piston is a one size fits all, as far as, A, B, C, D clyinders go, could the piston been too small and i should have waited for it too expand? Do you guys have any clue as to what might have been happing?