My new (140 miles) 450F has some wear on the subframe to the left of the chain due to chain contact. I checked the slack, and it is within spec. I thought maybe it was just from tipping over on the left side with the wheel spinning maybe, so I taped some folded paper on the spot and rode (without tipping! ) for about 40 miles and the paper was worn through. I asked a friend with an '03 and he said he has no wear there. This doesn't seem like it should happen so regularly, does it?