well I have a 93 katana 600 just got it and the guy I got it from had just put another engine on it and gave me the old one the old engine runs good nothing wrong but was missing 2 gear and there was nothing wrong with this engine just no spark but I went and tryed to jump it to get it to turn over the batery was dead and I wanted to trouble shoot so jumped it and it back fired then started after alittle bit but it doesent want to idle and when it does idle it is ruff and if you hit the gas it just dies right away and the headers smoke if I play with the choke to keep it running it will jump to 4 thousend rpm then drops down to 1 thousend rpm was woundering what can cause this to happen cleaned the carbs and re ilined the butter fly vavles and after that I can get to run alittle better but still ruff so any ideas please help