I removed the swing arm bearings before I had the swing arm powder coated. The swing arm bearings are the same sealed bearings used on the 1983 R100RS that I previously rebuilt so the procedure for replacing them on the R80ST is the same. In this document I link to the previous documentation for the 1983 R100RS as appropriate.
Earlier versions of the airhead swing arm used traditional bearings with a separate inner and outer race. I show how to replace that style swing arm bearing here.
I use a blind bearing puller set that I got for about $60.00.
I needed to fabricate a collar to remove the inner race. This shows how I fabricated the collar.
I use a large socket that is about 42 mm in diameter to drive the sealed bearings into the holes in the swing arm. The bearing diameter is 40 mm so the edge of the socket fits on top of the outer race and does not touch the inner race.
I got the sealed bearings (BMW Part# 33 17 1 241 546; EME Part# SABearing546) from Euro MotoElectrics which graciously agreed to support me with parts for this rebuild for charity project. When I’m done I’ll auction the bike and all the proceeds will go to the Motorcycle Relief Project.
This is a short video showing how I remove and install the sealed bearings.
VIDEO: 1983 BMW R80ST Replace Swing Arm Bearings
Remove Swing Arm Bearings
Removing the swing arm bearings destroys them. Here is how I do it for the 1983 R100RS.
Here is an R80ST bearing after removal.
The R80ST outer races show brinneling caused by the rollers hammering the outer race. This is a common condition since roller bearings don’t rotate completely when used in a swing arm so grease doesn’t get distributed around the rollers and eventually the roller is in direct contact with the outer race.
Install Swing Arm Bearings
The R80ST swing arm is designed for a monoshock and both holes have a solid metal bottom. The dual shock swing arms use a steel blanking plate (BMW part# 33 17 1 239 812) in the left bearing hole to keep grease from filling the swing arm crossover tube. The R80ST does not require this blanking plate.
The sealed bearings have a plastic dust cover. I use a knife to get under the edge of the dust cover and then pull it off before installing the bearings.
Here are the markings on my new sealed bearings.
Here is how I install the sealed bearings in the 1983 R100RS.
I can drive the left side bearing into the hole using the socket and a hammer by resting the swing arm on my work bench.
Due to the design of the R80ST swing arm, I wrapped the swing arm tube in shop towels and rested it on the rubber jaws of my vice so it would stay level while I drove the right side bearing into the hole.
Here are the R80ST bearings and dust covers installed in the swing arm.