34mm keihin carb jetting

[Evan]

Hello All, 

I own a 1995 Yamaha Banshee with the following mods: Keihin 34mm carbs, T5 full exhaust, cool head (stock bore Weisco pistons) and a Tusk heavy duty clutch kit, I may be missing a thing or two. The banshee runs great, and does so for about 30 mins, then the bike loses power, and the left pipe stops smoking. I have attempted to change the plugs does nothing. However, if I let it sit without running the motor long enough the bike regains the power on both cylinders (almost as if the carbs fill back up with gas, etc) I believe it to be a jetting problem. Here is the question, based on the mods which also includes K&N air pods what jet and main pilot size should I be using and or is it another problem, btw the cylinder head only has about two hours on it and the pistons only have a few hours on them. I should also add that I live in philadelphia Pennsylvania.  Please help. 

[Ayesully810]

what do the plugs look like? if it runs great and then runs like crap after it warmed up its probably too rich, if you shut it off and let it cool down completely and the cycle repeats thats a rich condition, also a symptom of an electrical issue but will likely happen sooner than later once warmed up like your describing. 

verify all electrical components are within spec.  before you start doing stuff with jetting. 

then see what jets are in it right now. 

Edited December 22, 2018 by Ayesully810