Years ago, by big brother had a used horizontal shaft small engine, an old minizbike frome with handlebars, springs, and sheels/tires, and a centrifical force clutch. He couldn't get everything to fit, so I bought it off of him. Using spare metal, I welded in a mounting plate for the motor, moved the fuel tank above the frame, and mounted the motor. I bought some chain and a 23-tooth jack sprocket (just a guess on size). I used a board, some foam, and leftover vinyl to fashion a seat.
This got the bike running, but there was a fuel leak that dripped onto the exhaust, and I had to manually manipulate the throtyle, which required sticking my fingers next to the exhaust. So, I bought a wrist throttle and csble, which came with grips for the bare handlebars. Some JB Weld fixed the fuel leak. It had a rope pull start, using a cylinder with a notch in it.
This got me up and running in style, until I broke the pegs off. Some welding and steel later, the pegs were good, but then I went over a jump, and the front wheel fell off. We welded some tabs on to fix that. The bike was great. Top speed of about 26MPH, and I rode it all over--often with 2 of us on it. Eventually, I replaced the rope pull start with a proper retractable pull start.
After about a year, I removed the governor on the motor, and it ran even better--until it put a rod through the case. I couldn't afford a new motor, and the bike was lost in a move.
Fast forward 30 years, and the bike re-surfaced. It had that same orange seat, and my welding. The frame has some rust, the tires have been replaced, and it has a blown 2-stroke motor. For old time's sake, I replaced the motor with a used 7HP 4-stroke (my original motor had been a 2.5HP 4-stroke). Someone had changed the gear on the jackshaft, and the throttle cable was jammed. I replaced the throttle cable. The spring on the clutch was too loose, so I removed the bad parts of it. The brakes were shot, so I rebuilt them, and fixed the broken rear brake. The carbreuter was messed up, so I rebuilt it.
The bike was fairly nice. If brake-torqued, it will pull a wheelie, and ride it for a bit. It has a top speed of about 60MPH, but put out a lot of heat. The kid really liked the bike as it sat, so off he went, with my admonishment to get a helmet.
That was several years sgo. Yesterday, the bike showed up again. It wouldn't start. I should note that it still had my JB Welded tank. So, my dad removed the pull start assembly, and put a device on the motor to get the motor running. The motor will run on its own, after being started, but will not start on its own. The compression seems to be low in the cylinder. I suspect bad rings or worn cylinders. Anyway, the frame was broken and re-welded, which I believe compromised the hardened steel, so I'm thinking that the bike is done. The only horizontal shaft motor I have left is a 26HP variety, but it is a more complex motor, and way too much power for that bike.
To think, my brother got that frame from a junk heap, all those years ago.
