Im having trouble with my 2001 WR 426. The chain is slapping continuously. When i accelerate hard from the bottom end up, or if im trying to cruz at a steady speed, the chain seems to slap at about 2 times a second. The tightness is to specs, i have checked it over. Also i am running lid off, vortip and i am at sea level. I am experiencing a random temporary studder at 1/4 to half throttle. I am still running stock jets. Does anyone know a perfect combination to smooth this problem out? Thanks so much.