I just bought a 2006 v star 1100 classic. I brought this bike home and was gone for about 3 months. I had put stabalite in the fuel before I left. I had noticed when I rode the bike home from the dealer it had a lot of rumbling at lower speeds, but when I picked up speed it seemed to mostly disappear. This bike does have staright pipes and 7700 miles on it. A BMW mechanice told me that the back cyclender was not firing at low speeds, runs graet 70 to 80 mph. Any ideas?