Motorized Bicycle - Winter Project 1 from Spike Category: On-Road Fabrication

[Spike]

Instead of gears it would be better to just add a centrifugal clutch from a small go-cart or spend the money and get a constant velocity drive system for it. All those little crappy 2 horsepower go carts get going from a standstill, then this bike can too. It'll add a bit of weight and some noise, but it should be able to get you going from a standstill.

But without a positive clutch, you would need another method to start it. I'm sure with a few tweaks you can get enough power to have a standing start. I see some of those are tweaked to go 50+ MPH.

The more I see this, the more I want to build one. If you added gears, do you think it would be able to take off from a stop?

Absolutely. You can buy a jackshaft kit, which replaces the bicycle's front crank and runs the engine's power through the bicycle's existing gears.
I've seen people getting up to 55-60mph with gear kits like this, and they start from a stand-still using the engine's regular clutch... so they still start the same.

Another option for adding some fuel economy, get up and go, and top speed, is to use an engine out of a little dirtbike with a CVT transmission (and a kickstart). I plan on building myself one of these with a 50cc 4 stroke engine from a dirtbike with a CVT transmission and an auto-clutch. with the CVT the engine can be even smaller and ends up working better.

[agent4573]

I completely forgot the only way to start it was to pop the clutch. Forget my idea about the centrifugal clutch. I think if you go with a kickstart motor it falls under dirtbike/moped and has to be registered differently than if you just use the bicycle pedals to get going. A few pedals really isn't a big deal if the motor is doing the work 99% of the time.

[Spike]

Break In, Break Down, and Final Touches

Whenever i sell a motorbike, i put at least 20 miles on the engine to get the break-in period over with and work out any would-be problems before it gets shipped out.
This particular engine had a problem, and not a common one. Aside from having a terrible intake leak problem, there was a bunch of crud in the engine case from manufacturing that got sucked into the cylinder and scarred up the piston and rings. Like i've said before, it's good to buy a local engine if you can. All i had to do was take it out and do a warranty exchange it for a good engine.

This picture also shows one of the upgrades i put on the engine. I throw out the junk spark plug that comes in the kit, and replace it with an E3 spark plug. Works great, and i've never fouled one yet!

During the second 20 mile break-in i realized i needed a place to put my drink, so i made a quick little cup-holder for the handlebars.


After the break-in it was all ready to hand over to the customers.

[Spike]

All Finished

[DVA]

During the second 20 mile break-in i realized i needed a place to put my drink.

Road Pop???

[Spike]

Road Pop???

:: facepalm ::
no... not booze. Coffee, soda, or usually just water.

By the way, drinking alcohol while riding a bicycle still gets you a DUI in most places.

[Jason]

The 50cc idea would be pretty sweet. Are you making your own front ends?

[Spike]

The 50cc idea would be pretty sweet. Are you making your own front ends?

I didn't make this front end, only modified an existing one. Though i could easily make one, and it would be a far cry better than the one i bought. Isn't that usually how it goes?