Avid cyclist looking to build 1st motor bike

[turb0_ryan]

After tearing down and restoring an old 70's Schwinn road bike from scratch and maintaining a fleet of 5-6 bikes of various types, I am looking for a more challenging winter project.

Buying a moped or scooter would be nice for getting around town more quickly, but that would be too easy.

I race mountain bikes and am very comfortable on a 26 inch front suspension build, so I am looking at buying an older steel frame mountain bike and retrofitting a motor.

I would prefer USA made kits/parts and am leaning towards a center frame-mounted motor for better balance and center of gravity.

I am in the very beginning of research into this, so any help in the right direction is welcome.

Thanks!

 

[happycheapskate]

I don't think there are any US made bike engines, but Grubee and BikeBerry.com are well known US based importers that sell the 66cc chinese motor kits.

The stock china-kit in-frame motors are ok, but the stock idler wheel and sprocket adapter (rag joint) leave a lot to be desired.

Check out bicycle engine kit, bike engine, bicycle engine, bicycle motor for friction drive and chain drive rear or front rack systems that take a variety of engines (pull start, look like big weeder engines).
Dax also has the in-frame engines.

Bikeberry.com has the in-frame engines, and sells 36 tooth cogs and metal "pineapple sprocket adapters" which will simplify your build a LOT and make starting easier and top speed faster. Good luck and welcome to motorbicycling!

 

[The_Aleman]

Welcome to the forum!

The closet you're gonna get to an all-US "kit" is to do what culvercityclassic or msrfan are doing.
American-made Briggs motors with custom drivetrains. Everything else is commie or a commie copy.
You could also get a GEBE kit, but then you're marrying yourself to a rackmount.

 

[turb0_ryan]

Thanks for the replies.

I have a friend who welds, so a custom drivetrain is possible.

USA made would be nice but if it's going to be a PITA, I am open to other options.

Currently, I am looking at picking up a single-speed steel frame mountain bike with disc brakes.

What should I be considering when measuring the frame, chainline or other geometries? Can any frame-mounted motor be made to fit with slight adjustments or should I be looking at a specific type of bike to make mounting the motor easier? From my initial research it looks like most motors are made to fit 26 inch wheelsize frames.

Also, what are the power/reliability/quality/exhaust smell differences between 2 and 4 stroke motors?

 

[CTripps]

For the 66cc motor kit you'll need 15" on the seat tube and 15" on the downtube. If you print this out to scale you can hold it to the frame and it'll also give you a good idea of the engine size. You'll also need at least 5" between the cranks to clear the motor and exhaust.

Good luck, and welcome to the forum.

 

[virginian]

I was and still am an avid cyclist. I put the GEBE Tanaka 32cc setup on an old mountain bike and it works great. I love riding it. It still feels and pedals like a real bike. I have over 5000 miles on it and it has never broken down on the road.

 

[turb0_ryan]

I put the GEBE Tanaka 32cc setup on an old mountain bike and it works great. I love riding it. It still feels and pedals like a real bike.

Thanks for the input.

I do like the simplicity of the design over a frame mounted kit, but I assumed the rear mount would make the bike feel strange in turns or quick maneuvering.

Having more clearance for pedaling with the motor in the rear is a bonus.

Also, would it be possible to build out a separate rear wheel for use with the motor and swap it out with a standard wheel if I want to go back to motorless? How long do you think it would take to swap? This would save me buying and 'restoring' an old frame for this project and just use a bike I already have. I could also then use it on my mountain bike or road bike depending on weather.

 

[virginian]

Thanks for the input.

I do like the simplicity of the design over a frame mounted kit, but I assumed the rear mount would make the bike feel strange in turns or quick maneuvering.

Also, would it be possible to build out a separate rear wheel for use with the motor and swap it out with a standard wheel if I want to go back to motorless? How long do you think it would take to swap? This would save me buying and 'restoring' an old frame for this project and just use a bike I already have. I could also then use it on my mountain bike or road bike depending on weather.

I was also worried about how the rear motor would make the bike feel. I found that it doesn't affect the feel of the bike at all. The bike still feels totally balanced.

To remove or remount the GEBE motor assembly is quite easy. With a little practice, you could do it in about 10 minutes. All you do is loosen the axle nuts and unscrew the support strap. Then detatch the throttle cable and kill switch wire, which is easy if you attached them with a velcro strap. You don't even have to change the wheel as long as you don't mind the plastic drive ring remaining on the spokes.

 

[happycheapskate]

I agree, the rack mount designs do leave you the easy option to use the bicycle as a pedal only bike. The first time I saw or heard of motored bikes in America was when I talked to an old man who was riding a road bicycle with a chain ring mounted on the front wheel. I thought it was just for looks, and asked him about it. He said it went to a motor and told me about bike engines. He said there was no point in taking off the cog because it didn't really affect his pedaling (century rides and charity races), but the kit came off easily.