This bike has 83,000+ miles on it and the wheel bearings are of unknown condition. So I replace them and set the wheel bearing preload. I also had the wheels powder coated after I removed the old bearings, so I had to also remove the disk brake rotors. I show how I remove, refinish and install the disk brake rotors in this document.
Of course, you can remove the wheel bearings without removing the disk brake rotors.
Here is a link to the documentation about how I do this work and to a video summary.
VIDEO: 1983 BMW R100RS Replace Wheel Bearings and Set Bearing Preload
And some pictures highlighting the work.