Engine Whine

Ok guys I have a slight problem that has me baffled. I have a Kawa Z650 F4 from 1983. When I start the engine it revs fine if a little rattly from the clutch basket due to the dampers being very old. When I ride it is fine as well except for a strange fairly high pitched whine that changes frequency up and down. The snag is that it is completely independant of both road speed and engine speed. But as I come to a stop it disappears until I am moving again. I have two possible targets one easier to deal with than the other, a possible wheel bearing on its way out(easy to change) or a gearbox bearing failing(more complicated repair) possibly on the output shaft as it is only obvious when moving under load. Does anyone have any thoughts about this.

Here's what I would do to try to isolate the problem. Find a deserted road. Get the bike up to speed at least to the point where you hear the whine. Put the transmission in neutral so you are drifting along at a fair speed and shut off the engine. If the whine continues it is unrelated to the engine itself since it is no longer running. With the engine off you may be able to tell if the whine is coming from the front wheel area, the rear wheel area, or the engine sprocket/transmission area. If you can isolate it to one of those areas finding the source should be easier. Ed

That's a clever idea I'll have to give it a try. I have tried with the clutch in and in neutral and the noise is still there but did not think to kill the engine.