Riding to work this am and start hearing a light rubbing sound, get to work check it out and the rear sprocket (wheel side) retaining lip has come off (and dangling around the rear axle!). The sound is the belt(now displaced 1/4-1/2) rubbing against plastic guard. The fiche shows the sprocket as one piece. Anyone heard of this happening? My wheels are correctly aligned with the axle cams in place butted up against the weld on the swingarm. What the heck?