I just put a 28mm keihin pwk on and it wont idle. It goes good when u get on it, but wont idle. I have an FMF exhaust, boysen reeds, No-lid airbox. I put a new cable on. It doesnt make a diff when i mess with idle screw or mixture screw. Do u think its dirty or do I need to adjust cable where it goes into top o carb? It was used!