I took a 400 mile trip on the bike today. About half way through the trip, a oscillating vibration set up. At first I was disconcerted and dropped my speed and it went away. It would reoccur like a switched turned on, but then fade away again. The speed and engine RPM stay the same unless I let them drop, so it is not a loss of power or slipping clutch. The vibration is felt in both the foot pegs and the handle bars. When stopped for gas, I felt the front hub-cool, final drive-warm, and transmission-hot, but I could keep my hand on it. With more riding, I could determine that below 65 MPH, the vibration was gone, at about 67 MPH it would start up again. As I am the type of person that hears hoof beats and thinks zebras, I thought I would ask for suggestions before I start draining oils and looking for particles. The bike is stock except for a Clearview windshield and the lower fairing removed. 58,000 miles.