I just purchased this '85 K100RT with only 15 K orig miles. THe bike is in excellent condition all around, however, now that I am over the intial excitement of owning it, I noticed that it has a small high pitched whine coming from the area just forwards of the alternator. I determined the location with a stethiscope. It sounds like a turbo charger whine , and it changes pitch when the RPM increases and decreases. I removed the alternator, cleaned it , spun it and the bearing seems fine. I lubed up the rubber coupling blocks upon re-install. This is my first BMW bike. Does this have a traditional throwout bearing like a car? Is the clutch plate loose? Any suggestions would be appreciated.

These bikes have a bit of a whine which I understood was a result from the combined oil/water pump on the front. Don't know if that's your whine, otherwise it could be an issue with the bearings of the internal gearing of the starter clutch and alternator gear wheels fitted in that area; the lubrication of these is not the best.

Run the bike with the alternator removed and have another listen.

The noise is on the rear of the engine, not the front. As I explained I narrowed the noise to that specific area by using a mechanics stethiscope. I aleady removed, cleaned and lubricated the starter. Then did the same treatment to the alternator, so its not those devices...

There are quite a few gears spinning around in that area and without a load many gears will whine.
My K100 has a very pronounced whine from that area and after much investigation including gearbox and rear housing removal I found nothing and decided not to be concerned unless it got worse. It has not got worse and I now just ignore it and ride. The bricks have a lot of gear noise but most of it comes from the straight cut gears on the lower 4 gears. The only significant problems that occur in that area is the sprag clutch and the rivits working but only on the six rivit shafts.
To be quite honest I would not be overly concerned unless it gets worse and then futher investigation would be needed.