I found a copy of the manual on-line which I thought would be useful. The first time I needed it was for the wheels. I fitted new bearings and seals taking care and kept everything very clean.
All went well and the wheels spun OK. When I clamped them on the axle the wheels locked solid. It's all caused by a shim number 748. The book shows it between the 6302 bearing 747 and the center spacer 752. What it doesn't show is the shoulder in the wheel hub the bearing fits tight against. When everything is clamped together the shim locks against both races of the 6302 bearing like a brake and stops the wheel turning. When I had a closer look the shim fits into a recess in the locking ring and keeps the grease in the bearing nicely.
I wonder how many of these bikes were assembled like the book indicates and ended up causing damage or even worse an accident. See what you think.