I wuold not buy a bike of that era and mileage unless I was able to check the splines. Like this:
Hey, here's a little write up I did on the spline check:
1. Put the bike in neutral and tie the clutch to the handlebar.
2. Remove the starter cover. There is a bolt on the inboard side of the cover which requires a long extension on your ratchet.
3. Remove starter and let it hang. No need to disconnect the wires. Let it dangle out of the way.
4. You will be looking into a vertical slot about 1/4" wide and 2" long. You will be able to see the splines on the input shaft.
5.The "front" of the slot is metal. That is the clutch cover. Just in front of that is the clutch itself. It is made of grayish brake pad material. Use a long, thin screwdriver to turn the clutch while observing the splines. The clutch and splines should turn in unison. There should be minimal play between the splines and the clutch itself.
6. Replace the starter. 15 ft-lbs on the two starter bolts.
7. Replace the cover.
Hey, two more tips for the inspection. If you look at the clutch parts fiche from MaxBMW (
MAX BMW Motorcycles - BMW Parts & Technical Diagrams - R1150GS (R21)) you can see part #5 is the part you want to rotate. Also, look at part #6. The flanges on the edge of part #6 can get in the way. You can use a big screwdriver as a lever against the teeth of the flywheel to rotate the entire assembly. It shouldn't take more than 10 degrees or so to give you a clear shot at #5.