80 year old club member selling vintage parts and has this complete engine sitting on shelf for over 30 years. It ran when put on shelf and spins over and has great compression. He thinks its a Hirth and I don't know. I listed tbe parts under parts for sale along with lots of vintage parts and a few sleds. Is this a Hirth? The numbers I found on engine are 2Z 340 0570 203. Am I reading it as a twin cylinder, 340, made May 1970, and was number 203? Just a guess. Anybody know ? Thanks for looking and thanks JD