I toured on my Bagger a couple of times and had the same thing happen. A kind of mild and steady pulsing. I found that it was related to weight on the rear—full saddlebags (what the little Bagger bags hold) and a luggage rack. I did have a bit of weight in the duffel on the luggage rack, and it is behind the rear axle, so I’m sure the effects on suspension are increased (as opposed to weight directly over the rear axle). When I removed the duffel and emptied the saddlebags, the pulsing went away.