Alright, let’s talk about putting together one of those 50cc motorized bikes. It was a bit of a project, lemme tell ya.
Getting Started – The Bike and The Box
First thing, I needed a bike. Dug out an old beach cruiser I had rusting in the garage. Seemed sturdy enough, frame looked like it had space. Then I ordered one of those 2-stroke engine kits you see everywhere online. Showed up in a box that looked kinda beat up, but all the parts seemed to be there. Lots of bits and pieces, instructions looked like they were translated poorly, but hey, how hard could it be?
The Engine Mounting Saga
Getting that engine crammed into the bike frame’s triangle was the first real headache. The mounting studs didn’t quite line up perfectly with my cruiser frame tubes. Had to fiddle with it, use some rubber padding that came with the kit, and really tighten down the clamps. Spent a good hour just getting it positioned so it wouldn’t wobble and the chain line looked mostly straight. Getting this part solid is super important, otherwise, you’re gonna have vibration nightmares later.
Rear Sprocket and Chain Fun
Next up was that big rear sprocket. This kit used the ‘rag joint’ style, clamping onto the spokes. Lining that thing up perfectly centered and getting it tight without bending spokes was tricky. You gotta tighten the bolts evenly, like you do with lug nuts on a car wheel. Go slow, criss-cross pattern. Took a couple of tries to get it running true-ish. Then, the chain. Had to figure out the right length, pop out some links with a chain breaker tool – which I had to buy separately, of course. Connecting it to the engine sprocket and the big rear one, then adjusting the tension… that took some fiddling too. Too tight is bad, too loose is bad. Found a sweet spot eventually.
Fuel and Controls
Bolted the little fuel tank onto the top tube. Simple enough. Ran the fuel line down to the carburetor, put the little inline filter in place. Made sure the clamps were tight. Didn’t want gas leaking everywhere. Then came the handlebars stuff. Swapped out the regular bike grip for the new throttle grip assembly. Ran the throttle cable down to the carb. Then the clutch lever on the other side, running its cable down to the engine clutch arm. Adjusting the cable slack for both took some trial and error. You want the throttle to snap back, and the clutch to fully disengage when you pull the lever.
Finishing Touches – Exhaust and Wiring
The exhaust pipe just bolted onto the engine’s exhaust port. Simple bolt-on job. It looked kinda cool, sticking out there. Wiring was surprisingly basic. Just connect the wires from the engine (magneto) to the CDI box, and then run the kill switch wires up to the button on the handlebars. The instructions were actually okay for this part. Double-checked the connections.
The Moment of Truth and First Rides
Mixed up some gas and 2-stroke oil according to the kit’s ratio. Filled the tank. Turned the petcock on. Choke on. Pedaled the bike to get it moving, then slowly let out the clutch lever. Took a few tries, sputtered a bit, then VROOOM! It actually started. Loud! Way louder than I thought. Let it warm up, adjusted the idle screw on the carb so it wouldn’t stall.
First ride was shaky. Felt weird having the engine power kick in. Definitely vibrates a lot. Had to stop after a few blocks and re-tighten some bolts that had vibrated loose already. That became a common thing. You gotta keep checking stuff.
Living With It – Checks and Maintenance
Found out pretty quick I gotta keep an eye on things constantly. It’s not like a regular bike anymore.
- Check the tire pressure basically every time I take it out. That little engine adds weight, ya know, and you’re going faster.
- The chain needs attention. Gotta keep that lubed way more often, and check the tension. Clean it if it gets grimy.
- Give the engine bolts and mounting hardware a check for tightness regularly. Vibration is the enemy.
- Wipe down the engine bits sometimes, make sure nothin’s leaking fuel or oil.
- Check the spark plug now and then.
It’s kind of a fun little machine, noisy and crude, but it gets you around. Definitely a hands-on project, not something you just build and forget. You gotta tinker with it constantly. But yeah, I built it, it runs. Pretty satisfying feeling, honestly.
