Greetings, I am not sure if this has been covered before. I have a 2000 RSV. Went out for a ride this afternoon did not get to the end of block and I could here a rubbing noise from the back axle.it was not constant but with every turn of the tire it faded in and out. I was wondering if any body might have any ideas what it might be???? Oil in axle is fine. thanx..