Hello, I am from Germany. I got an D4 Engine. Untill 1989 Germany was splitted in western Germany an the DDR (or maybe GDR in English). The DDR was in couse of the ****ing socialism political very close to russia in Germany called "Sattelitenstaat". Or "Sattelitestate" Russia was the Mothership an all those little states where the sattelites.
In the DDR they had many russian Products. Also russian Engines. A Few months ago i got a Russian D4 Engine, mounted to a Bike Made in DDR, Brand called Diamant. The Engine is ****ed up, its crank an bearings are rusted, some Threads are ****ed up and i dont have the Ignition. But maybe in a few days i will meet a guy who has an running engine mounted to a DDR Cycle Brand "Möwe". And some spare engines.
Sorry for the word ****ed up, but i dont know a an other word meaning the same. Sorry for my english, i learned it in school years ago.
After WW2 cycle Engines boomed in Germany untill the early sixties, then most people had enough Money to buy a Car or a real Motorcycle. And cycleengines died in western Germany.
A few of them are quite interesting, like the Lohman Diesel. 18ccm and 12.000rpm. No Ignition, self ignated like a Diesel, but it runs on lamp Oil and 2 Stroke Oil. Same type of engine like the old RC Engine, but mounted to a bike.
Lohmann-Fahrrad-Hilfsmotor-Testlauf Modell 51 "Nervensäge" - YouTube
I also own a Chinaengine, 50cc, mounted to a NSU Cycle with 3 Gear Sachs Torpedo from the early 60s. But now the engine does not run well. I think the cranks seal is crab. Ignition side its 14,8x27x3,8 but the other side? At the clutch?