Last weekend I repacked the wheel bearings on my '81 R80G/S. Here are some notes:
Neither the Haynes or Clymer manuals have an accurate blowout of the front bearing axle assembly for the '81 R80G/S, however the Haynes comes closest. The correct order of components (at least what was in my '81 G/S) from left side to right side was: oil seal, thrust sleeve (with larger end towards bearing), tapered bearing/race, long spacer, short spacer, race/tapered bearing, thrust sleeve (with larger end towards bearing), oil seal. According to the manual, it seems there are several configurations depending on which BMW bike one has. My R65LS and R100GS have the newer sealed bearings which require much less maintenance.
First I removed the thrust sleeve, this pulls out fairly easy through the oil seal. The oil seal that was in there had a metal surround with a hard rubber inner. The new replacement oil seal that I bought is all hard rubber. It was necessary to heat up the wheel surrounding the seal with a propane torch in order to remove. As Clymer suggested, I removed the rotor before removing the oil seals. This isn't necessary, but is probably a good idea so as to prevent possibly damaging it or getting it covered in grease. The manuals suggests either using an inside puller, or pushing outward from inside to remove the oil seals. Since I don't have an inside puller, I used a large flat blade screw driver inserted from the opposite end to push the oil seal out. I did this for both sides. They came out pretty easy with gentle taping.
I cleaned the bearings in WD40. The bearings and race were still as smooth as new ones, so I repacked them with MoS2 high temp wheel bearing grease, and put it all back together. Bearing and race come packaged together from bmw and are $20, which means $40 per wheel to replace. I think the oil seals were around $5 each. I ended up damaging the oil seals in the process of removing, primarily because I initially misread the manual on how to remove them. It's a good idea to replace them each time the wheel bearing are repacked anyway.
The whole operation was pretty quick and easy, but fairly messy since there's a lot of grease in there.
Dave Thompson
Champaign IL
'82 R65LS '92 R100GS '81 R80G/S
davet@roadkill.com (http://www.roadkill.com/~davet)