Hello ,,, I was refering to my old simplex step through scooter,... The early ones had a bolt on pulley and about 1959 started to weld on a larger pulley directly on the pressed ( or spun ) steel rim , also later models had larger diameter Idler pulleys , There were on the servicycles , at least a couple sizes of intermediate pulleys, member clwebster just purchased a primary belt from wayne, so I think that one would fit yours, ,,,,,,best to measure , I keep pieces of broken belts to wrap around pulleys to measure and get greatest accuracy, Best wishes ,,,,, : Larry. p.s. glad your engine is running , that must have been a real brain squeeze !
You get at least 10 gold stars for trying and an A+ for effort !