99 wr400. I ride my bike on the street and I have noticed that during hard acceleration my bike stutters like its fuel starved. If I merge into traffic it stumbles while its under 3/4 full throttle. Not off the bottom but in the middle of a hard accel. Bike is a one kick no choke starter and runs great otherwise. I have played with main size and needle position and have it about perfect except of course for the stumble.