Replacing a Clutch plate, BMW R50 1956

My very first few days of riding were not the way I had envisioned myself riding off into the sunset on my ‘new to me’ BMW. The R50 has a very easy clutch to engage but sometimes my hand would let the lever go a bit too fast and the front wheel would rise up and my hands would grip tight as the motorcycle would rapidly accelerate with a POP. Since I had just learned to ride on a very small Kawasaki about two weeks before I had the R50 running, the hand and gas combination had been a bit of a challenge for me.

One day while riding I notice the “slip” of the transmission, I knew I was in gear but it felt as if the clutch was not engaging. I had been riding now for about 5 weeks and had felt comfortable but I knew I would have to figure something out very soon. Coming back from lunch and first gear would not even allow me to roll. I ended up pushing my scooter about 2 blocks off the main road and back to my work. In the hot sun with my helmet and jacket on I was drenched in sweat.


My new Allstate insurance paid for itself as the tow truck back to my house was covered. That night I started immediately and had the transmission off and looking at the clutch plate.


Everything looked fine, but I went ahead (since I was there) and ordered all new clutch plate, clutch plate spring, friction plate and 6 hex bolts to upgrade to the old slot screws. The next weekend, once my parts arrived, I put it all back together, but to my surprise, the scooter still would not go… I removed the transmission and tested in first gear to verify operation of the final drive and check the slinger area.
Bingo! The woodruff key had been sheared off and the castle nut had not been torqued to the correct foot pounds.


This is a tapered fitting and required I also purchase a special castle nut socket. Purchasing a new castle nut and woodruff key I waited.

Castle Nut!
Castle Nut!

Reassembly was fast, I could feel the excitement in the air that summer night as I put the R50 all back together. Leaving no bolt, washer, screw and connection checked and rechecked for correct assembly.


That night I did a test ride and perfection, a new clutch and correctly assembled final drive shaft. My experience was sometimes frustrating, but at the end of the day, with the ‘scooter’ back on the road, I felt a good sense of accomplishment.



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