I dont know the exact symptoms of your problem. I had a problem once where my motor would, when I reved it up then closed the throttle it would idle down rather slowly. If I tried to let it idle it would only idle for about 5 seconds then slowly idle down slower and die. If i tightened the idle screw I could get it to idle at like 3000 rpm's, any slower idle and it would slowly die. Bike was very hard to start also. Tried several things like tightening bolts on the intake and such and nothing worked. I pulled off the right side engine cover one day and noticed the crank seal was in 2 peices. The inside ring of the seal had torn from the outter ring of the seal this was letting the crankcase leak air. I replaced the seal (getting that little gear off was a pain in the butt!) and my bike ran like it was brand new. Had more power, the engine was super responsive and it idled super smooth. Then about 300 miles later the problem came back. Same deal, torn seal. I looked at it really close and noticed the crank had 1/16''+ of play inside the crank bearing. The real problem was the bearing. This motor had over 3000 miles on it so rather than crack the thing apart and fix it I replaced the motor. I hope this isnt your problem. Hope you get her going soon.
