It's been a while since I wrote about my DKW SB350 restoration. In March 2025, after I got the bike back from Kim's, I took it on a couple of short rides, including taking it to Arthur Grady Day in Fremantle on 17 March. The bikes performance was quite mediocre. First gear was nearly useless and speed was slow. I decoked the exhausts, which reduced smoke but that did not improve riding performance. When I first rode it, it would fire up after only a few kicks, but now it became increasingly difficult to start. Consulting with other owners online, I was advised that the gearbox oil/grease mixture described in the original owners manual was too thin and would cause the cork and steel plates to slip. This also explained the poor traction in first and second gear, so I obtained the recommended lubricant - semi-solid grease from Penrite - drained the gearbox and refilled it.
My bike looks pretty shabby, but the engine cases are polished up.
Semi-solid grease is exactly like it says on the tin - think and goopy. The immediate effect was that kick starting improved, so it seems there is more traction on the cork and steel plates. However, gear changing became impossible. One of the problems that Kim and Wayne had highlighted early on was the replacement clutch cable I had purchased at the start of the project did not fit the bike, being almost a foot too short. Why are so many replacement parts crap?!! We reused the original clutch cable, which fortunately had tension adjusters at the top and bottom. that allowed me to get the right tension, but being old and stretched, it would slip and loosen very quickly. This exacerbated another problem - the worn out clutch spindle. Here is a video showing how worn out it was.
When the clutch cable is tight, the spindle is held in place, but as the cable stretches, the spindle wobbles all over the place. The problem is that there are almost NO spares for this part. I was searching for a NOS part for almost six months before I managed to get my hands on one. It was very expensive but.... what can you do?
An engineering company in Germany has subsequently begun manufacturing this part. They can now be purchased through
ebay.de.
Link to the shop:
https://www.ebay.de/itm/127467977064
I also bought another clutch cable, which turned out to fit correctly this time. I've put the bike back in Kim's hands to put it all back together. Hopefully this will sort it out - crossed fingers!
Previous update:
https://dkwautounionproject.blogspot.com/2025/05/1938-dkw-sb350-restoration-update-coal.html
Update 28 February 2026Kim sorted out the clutch - one of the discs needed re-corking as the height of the corks on one disc was insufficient. The spindle and the new cable made a big difference but then the kick start spring snapped. Kim found that drive sprocket was worn and loose. There was also play in the crankshaft, so we agreed that we'll pull the engine out, strip it down and rebuild it. I had assumed the engine had been rebuilt when I bought it but it seems it was only recommissioned. There you go! More update to follow.
