I have a 1996 shee and iv just rebuilt it and we have namura pistons and well we seem to be having alot of problems with this (hint dont buy used) well heres my question if you guys can help when i start it and let it run for a couple of seconds its reving starts to go higher and higher and than it starts just screeming and when i feel the exhaust i got smoke and pressure comin out one but not the other than it revs and like switches and sometimes there both fireing perfet, is it miss fireing and needs a new CDI box or reeds or is it just my carb but i need help in the next 2 weeks gotta get this fixed going to the mountains and driven down there but please if you can, tell me anything u can every idea is good right about now