If it really bothers you, you might have to get the crank trued. It is my understanding that the crank QC is not as good as it could be so that some with a good crank hardly vibrate and other vibrate lots. It did not seem to get better with later years. My 92 does not vibrate at all, other than being a 500. As Hughes says, worn main bearing can also cause some (or all) of that. It is important to use higest quality main bearings possible, last longest and tightest clearances. Cam.