Thought I could buy a new pair of piston rings, but it turned out that this wasn’t quite doable.
The only piston rings that I could aqquire looked like this:
One being wider than the other, but the old piston had two identical sized piston rings:
This forced me into buying a complete set with piston and rings, and mount that instead. The complete set did not cost much more than the rings did on their own, so after all a reasonable expense.
The install went pretty smooth, and I managed to push the cylinder head over the piston, with a bit of patience and perhaps most importantly; oil.
The good news: After having put everything back together, I managed to start the bike in the first kick.
The bad news: I was only able to drive it with the choke on, and it drove around 15 – 20 km/h. As soon as I turned off the choke, the engine died on me. Now I’m not even able to start it anymore.
There is flowing fuel to the carburetor, and there is spark. There is however another problem. There is all of a sudden no compression, I could nearly push the kick starter down with my finger.
I fear that the piston rings might have broken, and damaged the cylinder, and ruined it completely. I fear that this project will more expensive than first calculated with…
Update will follow.