Look at the (Moon Dog), my Green Hornet, I think that is what it is called, from W Mart. The reason I am saying this is that the frame is so small the engine just fits. I needed to take the top end off and had to take out the studs to get it off with-ought taking the engine out. What I am thinking is that, it being so small that it has strength! I used one of those flat plates to hold the engine in the front, I don't like them, but it is still smooth running. I would like to exchange the engine from the Schwinn but I don't want to mess up the paint, I would like to see if my idea is correct. Have fun, Dave