This is too weird...and I'm not joking. I started hearing some type of infrequent "clank" pretty much exactly as you described it on my ride today.
The Destroyer Approaches
"Living life is a great idea, but riding a motorcycle actually gives you a tool to do it..." -me
2013 Sunset Red Cross Country
Vic Tri-Oval Mufflers, Lloydz AF, ATS+2, PC-V tune by Dyno Solutions
Drag Specialties low-profile Touring Seat, Klock Werks Klip Hanger bars
Kuryakyn ISO grips/bar ends and SwingWing rear boards
Victory black LED headlight and Touring Pack, Madstad 9" windshield