Thanks for all the replies on this engine! The friend who has this engine tells me that the fan shroud has Flying Merkel stamped in the metal and that he (foolishly I think) cleaned the rust off and painted it. Since I have not seen this engine, I can't tell you much more about it than he has told me. The carb can't be seen in the one picture I have of it, but I was told that a weed eater tank was rigged up to it so it could be started. It has an atmospheric intake valve, and a pushrod exhaust valve. I hope to see him again today, and will try to get more photos of the engine from different angles. I googled ' 1912 Flying Merkel ' and all the photos show a different type of engine than this one, and shortly after (like 1913) Merkel went to the twin cylinder engine. Like some of you, I'm having some doubts that this engine ever was used on a motorcycle type bike. Does anyone know if Merkel made single cylinder motorbikes after 1912? Did Merkel make engines for staionary applications? Was Flying Merkel a company name or just a model name for boardtrack racers? I'll try to get to his place and look at this engine in person, and get back to here later. Thanks again guys!