Mine did the same thing except no dent. I accelerated pretty fast and the seat went sliding back with a "pop" (that was the fender nut going bye-bye), and I was suddenly sitting about 8 inches further back. Scared the crap out of me. I dropped by the local H-D shop on the way home and they said they had been seeing lots of that, and showed me the little metal bumpers that bolt down on top of the frame, under the seat, where the front saddlebag guard would go. Anyway, they replaced the fender nut and installed those 2 little pieces on the top of the frame, no charge.