I'll start from the begining, I bought this bike a year ago with a bad trany, fixed the trans. installed all new seals and gaskets. reused top end because it looked good. bike ran awsome. the only problem it had was it would missfire on right side untill warm. checked compresion about six months ago and it was 120 with stock head and no port work. last Saturday went to dunes, bike ran awesom for about ten minutes then started crapping out, the right side was firing intermittantly,and left side was back firing out exhaust, moved plug wires around, checked reeds, checked carbs, synced carbs. all ok. checked compression and it was at 85 psi on both cylinders, so I pulled top end off and currently rebuilding. My problem is I've been told that low compresion won't cause the problem i'm having. any body have sugestions. also tors are removed and so is rev box. Thanks