Steve,
Had the same thing happen, earlier this year...
Headed out of the garage, pointed East, with the wind at my back. Had her up to 55 - 60, and all was well. Turned North, now a good cross wind, and for a few miles, held her down to near the posted speed of 35. Once out of the populated area, took her up to 60, when I got this awful buzzing, just as I topped 55... Slowed down, buzz was gone, sped up, and it started right at 55 again! Was checking everything I could touch... Windshield, fairing, windshield pouches, tank bib, anything within reach?!?!? Then I turned my head sideways, and the buzzing was gone. Touched my visor, and the center snap was undone. Snapped it back, and no more noise!
A very unnecessary panic attack

Black Dog