Did you adjust your chain tension lately or the preload on the rear shocks? The chain will have the most slack in it when it's on the center stand so you may not hear it when testing while on the stand. If the chain is too tight, it will sound like a turbocharger and the pitch will vary with speed.
It may be the tires. I've got Road Smart IIs on my Concours 14 and it makes a whirring sound from the front tire when the bike is leaned over in a turn.
UPDATE... man, these CB's are amazing; they've even figured out how to fix themselves!! Lol... I rode the bike yesterday over to Powersports Honda in Largo, FL. and on the way there the noise disappeared. Go figure! I heard it for a bit, but then it disappeared... never to return. And since I don't like chasing ghosts, I turned around and went home. Oh well... glad it's gone!
Awesome R4N , ya gotta love it when they are "self healing"
perfect solution!

So just the threat of the forum knowledge did the job
Nice one

(10-10-2016, 03:01 AM)JustCruising_imp Wrote: [ -> ]So just the threat of the forum knowledge did the job 
Nice one 
That's it!!! The collective power of this group made it fix itself or else!
Man, you guys are good!!!