I have an '11 Vaquero and it has developed a harmonic noise in the rear. It only happens at 25-27 MPH and seems to be getting worse. Don't laugh (or do) but it goes woo woo woo woo and is really anouying. It definately got worse after I had the rear tire changed. I called the local dealer and they can't get it in for 6 weeks and they want me to leave the bike with them the entire time. The guy thought it might be the belt but I can't see any wear. Any help would be appreciated.