Try removing the airbox lid. Also what size jet did you install with you rebuild? A few thing play a role air/fuel mixture, leaks, jet size, sprocket sizes... If you changed the jet check your pilot screw. supposed to be around 3 1/2 turns out from seat with a stock jet if you went larger turn it out in 1/4 turn increments until you acheive the highest idle possible then turn down the idlestop give the pilot screw another 1/4 turn and let it be. rid the piss out of it and do a plug check. if it looks like coffee with creamer in it your good. And don't run anything less than 93 octane in it.