got a prob with my 88 classic in that i get a vibration at anything over 40 mph it almost feels like the props but i have changed all uv's , wheel bearings and cv joints and obviously wheels and balancing are fine. it only seems to do it when i'm accelerating, if i coast it stopsany ideas? also sometimes when i put it into reverse on totally flat ground and move very slowly it feels like i'm running over bumps??