After we discovered that the clutch was not really operable, the clutch basket was pulled from the bike and I ordered a new set of cork plugs. These arrived surprisingly quickly from Germany on 11 April. See the proceeding post for the details here: https://dkwautounionproject.blogspot.com/2025/04/1938-dkw-sb350-restoration-update-march.html
I had cleaned up and polished the metal plates in the proceeding weeks. The condition was pretty good as far as I was concerned.
I had some time over Easter so I set to it. The cork plugs are twice the height required in the clutch, so each plug was cut in half using a craft knife. Some plugs were a little more accurate than others but all will need to be sanded down to a flat surface when they're mounted in the plates.
The cork needs to be boiled to make it soft and pliable enough to fit in the holes. Half an hour on a rolling boil was enough. It must be noted that once out of the hot water they cool down very quickly, so it's best to fit them in small batches while the rest 'cook.'
To my surprise, the cork was very easy to install. There was some inevitable losses due to seams and weaknesses in some of the cork plugs, but the bags contain more than sufficient for two sets of clutches.
The bottom plate was actually the easiest to fit.
It took about half an hour to fit all the small plugs. The big plugs follow the exact same process.
Almost done.
Job completed. It was a very easy and quite satisfying task. Now, the cork needs to dry as they were thoroughly cooked out.
Once it was dry I gave each of the cork plates a good sand to make them smooth and flat. The cork sanded very easily.
The clutch 'reassembled'. The clutch plates will need a finer sanding to get them to the right thickness and fit. I will leave that to the experts to do as I don't want to sand anything down too far that would undo the good work above. Hopefully this will be the last fix before the bike can be ridden.
