Round and round like a bad song.
Just checked out a rear end noise on a Yamaha Star the other weekend. Guess what it sounded similar. Told the guy I thought it was the bearings. He took the wheel off, yes the needle bearings in the hub/cush drive were bad. The wonderful bike shop that changed his last rear tire, tightened the fruck out of the drive belt. Hang things to tight to long they die....... I personally would jack the front of the bike up so the tire clears. Spin it see how it sounds. Have somebody hold the bike by the bars and then try moving the wheel up,down, back and forth, see if you feel some slop at all in it. If that does not tell you anything then time to start taking it apart. If you do not feel any play or slop or ruffness in the wheel movement I would pull the brake pads off and try spinning it, if the noise goes away you got a problem in the brakes somewhere( I doubt that's it). So now if nothing has solved the noise problem, pull the axle out and drop the wheel out. Take your finger and spin the wheel bearings, if they are ruff feeling or noisey, time for some new bearings.
Buckeye, Arizona(USA) 2011 Victory Cross Roads, Black police bag guards, black engine guards, black handle bars, Triumph Tiger mirrors, Triumph hand grips, set speedo/tach back 5" , adjustable timing wheel, Lloyzz Fuel Programmer III & air filter. Modified exhaust, made stock into 2 into 1. MRA windshield, Rotated front fender forward,relocated ignition switch, Bad Ace Fuel Tank Risers, Fat front tire.