Using a 301cc Predator engine from Harbor Freight

This is going to be interesting because there is already a faction who thinks that Federal laws legalise E-Bikes to be accepted in all of the USA just like regular pedal bikes...These states are making laws to either regulate them and their use or trying to find ways to outlaw them like New York City is trying to do because of all the battery fires caused by them in densely occupied apartment buildings with many deaths resulting, etc.
Though not enforced throughout the state of NY, no self built motorized bicycle (gas or electric) is allowed to be operated on their public roadways. Only certified manufactured ones are allowed; which are becoming increasingly strictly regulated.

More so than battery fires, the biggest reason many states are coming out with these e-bike laws is due to reckless cycling behaviors being transferred over to e-bikes. It's bad enough when a cyclist uses unsafe cycling techniques but add extra speed/weight and the risk factor goes way up.
 
I suggest getting a more realistic speed in mind such as a consistent 45 mph and top out at 55 mph on 26" wheels. Then you'll have a few options to do this.

You can run a single left side chain and 2 sprockets 3~1\1 CVT 10t\50t sprockets.

Or you can install a double sprocket jack shaft to the seat post. Then use this setup:

3~1\1 CVT 12t>>[30t | 18t] JS>>36t Rear Wheel.

By keeping the rear sprocket to a 36t you can setup a rear 3 spoke mag wheel with a disc brake like Damien has. If you truly need to go faster than 45 mph then go buy at least what's classified as a motor-driven cycle or even a motorcycle.

View attachment 214497
The double sprocket jackshaft is a gear reduction I. Your set up? I do plan on eventually removing the gov/ balancing it. Ideally I’d like to efficiently ride around 45-55, so under what I’d assume from my mechanic knowledge with cars, you want to tune its top speed a little higher than what your cruising at.
 
The double sprocket jackshaft is a gear reduction I. Your set up? I do plan on eventually removing the gov/ balancing it. Ideally I’d like to efficiently ride around 45-55, so under what I’d assume from my mechanic knowledge with cars, you want to tune its top speed a little higher than what your cruising at.
Just like a street car you can't run full throttle all the time. Let's say you do mods to where the engine is able to give you an extra 2000 rpm without over heating. This doesn't mean you go to an even higher gear ratio to get more speed. You drop the gearing even lower to keep the same speed but gain more torque. This way should you encounter a hill the added torque means your speed won't drop going up the hill.

For example: To do 55 mph on 26" wheels with an engine rpm of 3600 you need 5\1 gearing reduction. If you were doing 5600 rpm to do 55 mph you'd need a gearing reduction of 7.88\1.

The best example I can give you it'd be like being on a pedal only bicycle being in a high gear and having to stand while meshing the pedals to get up a steep hill. Versus putting the bike in a lower gear increasing the cadence (crank rpm) to climb the hill while remaining seated. The majority of the time the low gear, sitting, high spin method is faster than high gear, low spin, standing meshing method when going up long or steep hills.
 
Back
Top