I have a 1978 suzuki gs400 and i am in need of rejetting it. i cant find jets for it anywhere. the reason i feel i need to rejet is because i have modified the exhaust and i changed to cone air filters. the bike will only run on choke and stays around 5,00 rpms. once i take the choke off if i dont keep the rpms above 2,000 by feathering the throttle it will just shut off. could this be a different problem? i have soaked and ran a fine tooth comb throught the carbs multiple times. even with theses mods i am thinking that i would still be able to idle but i am not sure.