Back in February 2026 I put the bike in the hands of my mechanic friend Kim to sort out the clutch. The clutch had completely failed thanks to a combination of the clutch cable being old, the clutch spindle being completely worn out and the wrong lubrication being used. Kim was able to insert the new clutch spindle, replace the cable and re-sand and replace some of the cork blocks that had broken apart.
However, when putting the clutch back together and attempting to tighten up the primary drive, he found that the crankshaft had an unexpected amount play. Unfortunately, Blogger does not seem to allow me to add a video here and stupid YouTube will not let me insert it here because it's a "short", so if you want to see the video - click here: https://youtube.com/shorts/OoXBjHcg6Zo?si=_s7gBsTZ5sh4uBKf This play is not normal, but not surprising in an 88 year old motorcycle.
So, it was time for the motor to come apart. All up, there was some wear of the bearings - which we will now try and source and replace - but the piston and rings were in reasonable condition.
I had often wondered what the difference was between the many models built in the 1930s. It seems to me that most of the differences were internal to the engine. In the SB models, the crankshaft ran directly on the bearings, which led to increased wear. Later models, such as the NZ made improvements to this situation and added in key-ways to improve traction on the primary drive.
Well, I had not planned on a full engine rebuild, but that's where we are. I've got some more parts to source .....
Previous update: https://dkwautounionproject.blogspot.com/2026/02/1938-dkw-sb350-restoration-update.html
