I put a TAV-2 30 on my Doodlebug. I run a HF 200 on it and at modest RPMs I get a slap from my drive belt bumping the cover. At more RPMs it runs good but, under some conditions it slaps. Sounds like a motor boat. Rub marks on the inside of the belt cover are at the mid point between the pullies-on both top and bottom sides. The belt is on correctly and the belt fit is tight-so tight it is a bit hard ( not too hard) to install it. Any help as to how to solve this?