Bob,
There's not much in the way of identifying marks on this engine. Just says "Webra-Austria" under the cylinder (exhaust side) and "WEBRA-61 on the opposite side.
The cylinder has cooling fins all the way down to the crankcase. Six (6) bolt head. Looks like three (3) ports in the cylinder. Ringed flat top piston.
Beyond that, there's not much more to, physically, describe.
I'll try to post a picture, but will have to wait until my son comes home from work with his digital camera.
Thanks for your interest.
Joe