For no reason in particular, I stalled out on the DKW project. I got to the point where I needed some engine parts, in order to reassemble it. After much inspection and measuring, I found the cylinder bore needed a bore job, I need a new piston, and I couldn't for the life of me get the sprocket off the shaft. It is a press fit onto a taper, held tight with a large nut. Apparently they like to weld themselves to the shaft.
I soaked, I heated, I soaked, I hit it with a hammer, I soaked some more, I installed a large puller pounded as tight as I could get with my 1/2" impact. Nothing.
Then...as luck would have it...I came across a guy in Reseda selling NOS DKW/Sachs engine parts. This was roughly four days before Christmas, and Susan's youngest Sister happens to live in Reseda, and was coming up for a visit. So I struck a deal for a new cylinder housing that cleaned up very nicely, a NOS piston kit, a NOS sprocket and nut, and a NOS set of points. All for the same price a DKW specialist shop sells just a piston kit for.
So the old seized sprocket had become redundant, and I decided drastic measures were in order. That meant getting out the angle grinder, and going to town on it. 10 minutes later, and a face and mouth full of grinding dust later, I was able to finally remove the sprocket, and pull the shaft out of the engine case.
So now I'm soaking the engine cases to help de-grime the past four decades worth of grease, oil, and dirt. One of the pain in the asses about heavily finned air-cooled engines, are the deep fins that collect all kinds of debris. I'm half tempted to find a local machine shop to dunk the cases in, before I give them a wire brushing and polishing.
Then, I need to order a set of bearings, seals, and gaskets for the re-assembly.
Exciting photos below proving I did do some work: