I had originally thought my wheel bearings were bad, so I replaced them though they looked ok, but the noise persisted. So I figured the cush drive rubbers were shot after 80,000 kms but had not yet replaced them. But tonight I had this idea of putting the bike in gear and trying to turn the rear wheel to see if there was a visible amount of play in the hub when lo and behold, the noise came out of the front of the drive chain. So it turns out the front sprocket was loose! This was last replaced at about 38,000 by the dealer under the factory chain/sprocket recall. The front sprocket is hooked now and does need replacement, as does the chain and rear sprocket, of course. But now I know what the cause of the noise is.