Wow! I accidentally stumbled onto this site and it's just what I was looking for. I won't be able to contribute much because I've never built a motorized bike before. (Whoops! That's not quite true. I did put a 1 1/2 hp Briggs and Stratton lawn mower engine on my Firestone bike back in 1958. Does that count?) I'm here to ask questions and learn. I'm on the verge of ordering a 50cc motor from eBay to put on a bike. I'm kind of handy, but no mechanic. I think I can learn pretty fast.
Looking forward to learning from the "pros" on this site.
Say that 1.5 BS must have been a cast iron one. I have restored a few of those. Oh but for lighter weight to hp ratio I have an 80's era 3.5 BS engine that to fit in a 60's JC Penny Foremost Bike Frame I recovered from the trash, had to put the engine on a 15 degree tilt back. It would not fit otherwise. Note the splash oil lube system it has is not adversely affected as the splash fork in the crank case is connected to the bottom bolt on one side of the connecting rod.
Serendipity has it that the side clamp of the bottom of the piston connecting rod makes a oval motion and dips into the oil toward the back half and moves forward and upward before getting past center of aft / forward of crank case sump as it makes it's was across and up out of the oil sump. Only I thought it may get into the breather, but it is only about an inch higher on one side. Valve tappets an breather have cam shaft and breather guard inside crankcase such I don't see that it will cause trouble. Not yet started with newer carb and with engine on tilt, but will report back on this. I made an adapter plate to the manifold to carb so that the bowl is level.
Welded with TIG much of the steel and just need to get my washing machine pulley attached to rear wheel centered better. It is done with ply wood and screws and had a blast back in the 70's when I was riding similar 24" vs this 26" current model. Also different is the gravity feed and bowl carb instead of the vacu jet type carb, plus a jack shaft to transfer the chain from centrifugal clutch to v-belt and line up the belt to back wheel. Now I can see about a non-lopsided (engine off to the side) motor bike.
Getting a chain / jack shaft / v-belt guard built without the welding equipment available will be a challenge, but there are enough points I can drill and add brackets to existing portions of engine platform I can access. If need be clamping to the frame I might have to do some of.
Measure Twice, or have a TIG handy if you plan on drilling the wrong spot
