Who has built a motorized bicycle?

[RC K9]

Has anyone here built a motorized bicycle? I don't know why, but I have had this itch to build one, and it seems like for someone who is somewhat mechanically inclined. I have a Zeda-80 kit on the way. Now just keeping an eye out for the right bicycle.

 

I live in a nice sized, unincorporated neighborhood with a big loop through it and a big sports park back behind that so I think this thing could be fun to putt around locally with.

 

That being said, has anyone ever built one? From all the vids I have watched, I know the standard mods people make a porting, good carbs, high comp heads, upgrading the CDI box and spark plug, expansion chambered exhaust, etc. I'll keep mine stockish for the time being since it will be my first build, but was just curious as to whether or not anyone else on here had any experience with them.

[Red Beard]

I do not own the bike but helped my buddy put his together.They are very simple and easy to do. Hardest part is getting a frame that works with the engine you have and making sure the sprocket fits on the axle. Typically older style frames work better (the ones with a swooping mid pipe) but a little fab work will go a long way with whatever bike you choose to put it on. Edited May 8, 2018 by Red Beard

[RC K9]

They are very simple and easy to do. Hardest part is getting a frame that works with the engine you have and making sure the sprocket fits on the axle.

 

Yeah, I am being kind of picky with frames...

 

I just wish there were better quality engines available, but that would be cost prohibitive, so we are stuck with flip of the coin Chinese motors from what I can tell.

[Geeto67]

I helped a friend install a friction drive gas motor on his bicycle in the early 1990's. It wasn't hard for a bunch of teenagers without driver's licenses to do. It's probably the cheapest way to get the motorized bicycle experience but budget for rear tires because it will wear them down fast.

 

My question is though, why do you want a motorized bicycle? Are you trying to replicate an old board track racing motorcycle from the 19-teens or a whizzer? or is it something else?

 

For that vintage look without buying a kit, I would consider a schwinn cantilever frame with a springer front end or a worksman delivery bicycle, just because both have a reputation for taking abuse:

https://cleveland.craigslist.org/bik/d/worksman-industrial-bicycle/6548540552.html

 

you are probably better off buying someone else's project and re-doing it than doing your own from scratch.

 

https://columbus.craigslist.org/bik/d/motorized-bicycle/6568152955.html

https://kalamazoo.craigslist.org/bik/d/vintage-motorized-schwinn/6543441190.html

 

Have you considered an adult tricycle? It will give you a nice easy platform to mount the engine and fuel tank to (between the rear wheels)

[RC K9]

I helped a friend install a friction drive gas motor on his bicycle in the early 1990's. It wasn't hard for a bunch of teenagers without driver's licenses to do. It's probably the cheapest way to get the motorized bicycle experience but budget for rear tires because it will wear them down fast.

Not really interested in doing friction drive.

 

My question is though, why do you want a motorized bicycle? Are you trying to replicate an old board track racing motorcycle from the 19-teens or a whizzer? or is it something else?

Why not. Fun little side project for sh*ts and giggles.

 

For that vintage look without buying a kit, I would consider a schwinn cantilever frame with a springer front end or a worksman delivery bicycle, just because both have a reputation for taking abuse:

https://cleveland.craigslist.org/bik/d/worksman-industrial-bicycle/6548540552.html

Thanks for the frame reference.

 

you are probably better off buying someone else's project and re-doing it than doing your own from scratch.

 

https://columbus.craigslist.org/bik/d/motorized-bicycle/6568152955.html

https://kalamazoo.craigslist.org/bik/d/vintage-motorized-schwinn/6543441190.html

Those are neat, but i'm not looking to spend $250-$300 on someone else's complete setup just to put more of my own time and money into it. I', looking to have around $200 total into the whole deal.

 

Have you considered an adult tricycle? It will give you a nice easy platform to mount the engine and fuel tank to (between the rear wheels)

No, but that's a neat idea. I'd venture to guess that takes some welding though, and I can't weld.

[Red Beard]

hell we use to make them out of weed eater/chainsaw motors and a centrifugal clutch.

[Geeto67]

Not really interested in doing friction drive.

 

Why not. Fun little side project for sh*ts and giggles.

 

 

No I get that. I mean it helps to have a goal in mind because it helps with parts selection. If you want to build an early motorcycle replica there are some very specific details you want. Old horn tank bikes make it easier to mount things like gas tanks and make it look old because they were designed to look like motorcycles to begin with. Schwinn made one form of tank bike or another until the 1970's so they aren't hard to find for cheap if you really look.

 

If you just want something to wiz around on, any mountain bike bought from Walmart for cheap will work.

 

 

 

No, but that's a neat idea. I'd venture to guess that takes some welding though, and I can't weld.

 

actually it's probably easier to mount and no welding. All those trikes are designed to have a basket mount behind the seat between the rear wheels. If you take it off you can bolt a wood board to the basket mounts and then just bolt the engine to the board. You run the chain directly to the high gear on the rear drive sprocket and keep the pedals on the low gear and ditch the derailleur. That way when you are moving slow you are pedaling and then when you need to go faster the engine kicks in.

 

electric bike guys like them because there is a lot of room for batteries and motor. Case in point:

 

hell we use to make them out of weed eater/chainsaw motors and a centrifugal clutch.

 

yeah any small gas engine with a centrifugal clutch will work. We used to use them for mini-bikes as kids. The secret is to get one with a low enough clutch speed so you can bump start it, some of our old mini-bikes as a kid took a big hill to get going because the clutch speed was high. The gearing does all the work in these scenarios.

[RC K9]

hell we use to make them out of weed eater/chainsaw motors and a centrifugal clutch.

 

How many CC's are those motors typically?

[Geeto67]

How many CC's are those motors typically?

 

Usually between 40cc and 80cc. some of the bigger heavy duty ones can run up to 125ccs but those are like industrial or competition saws (I think the STIHL 880 is 121ccs and 8 hp).

[RC K9]

Wonder if this would work. Not sure if there is enough spacing for the motor with that lower bar:

 

https://dallas.craigslist.org/dal/bik/d/schwinn-costin-bicycle/6583094249.html

 

Or this:

 

https://dallas.craigslist.org/mdf/bik/d/new-mens-bike/6582546953.html

 

Or this (though doubt there is enough space):

 

https://dallas.craigslist.org/ftw/bik/d/electra-comfort-cruiser-trail/6580750876.html

 

Hmm:

 

https://dallas.craigslist.org/ndf/bik/d/vintage-street-cruiser-bicycle/6568375698.html

 

https://dallas.craigslist.org/ndf/bik/d/schwinn-admiral-mens-city/6557448003.html

 

I dig this:

 

https://dallas.craigslist.org/dal/bik/d/vintage-mens-bicycle/6578315254.html

 

https://dallas.craigslist.org/mdf/bik/d/ross-vintage-bicycle/6543290779.html (Wheels may be too small)

 

https://dallas.craigslist.org/mdf/bik/d/western-flyer-vintage-bicycle/6543287801.html

 

 

So many potential options.

[JoeNova]

Ebay. 80cc bicycle kit comes with everything you need to convert a bicycle to an 80cc engine. Gas tank, chain/sprockets, engine and mounts, etc. Will do ~40 mph and get over 100 mpg. Kits can be had for $90 shipped.

 

Not a centrifugal setup. You'll need to pedal up to 5 mph or so and slip the clutch to start it. I put one in my daughters power wheels. Drifts pretty good now.

[Red Beard]

How many CC's are those motors typically?

 

Usually between 40cc and 80cc. some of the bigger heavy duty ones can run up to 125ccs but those are like industrial or competition saws (I think the STIHL 880 is 121ccs and 8 hp).

 

^^^^^ this, We usually just used what we could find. Most 50+ cc engines will have enough power to tool around on.

[RC K9]

The Zeda-80 kit is 66cc.

 

The 40mph on a stock would be with like a 28 tooth sprocket (no down low power), going down a steep hill, with the wind at your back, ha ha.

 

mid 20's seems to be the norm from what i've seen.

[Red Beard]

Right, they aren't torque monsters, but they do keep the revs going once you are moving. If you want something with more power/low end grunt, a small horizontal shaft engine would be better. Something in the 5 hp area would fly. We've built a few of those back in the day too. Usually we put them on a custom rack that hung over the back tire and ran a chain/sprocket set up.

[Green Bastard]

Not sure of the laws in Texas, but I believe in Ohio amything over 50cc you have to have a motorcycle endorsement (not sure about bicycles that had a motor added though).

[RC K9]

Not sure of the laws in Texas, but I believe in Ohio amything over 50cc you have to have a motorcycle endorsement (not sure about bicycles that had a motor added though).

 

A lot of states are that way. Not sure how a cop would prove whether the motor is 49cc or 66cc though.

[RC K9]

Built it this weekend. Just used a Huffy Cranbrook beach cruiser from Wally World. No idea how fast I got it up to, but it's scary. Feels all sketchy when haulin' @$$ on it, ha ha. Somehow doing 20mph in a car feels like moving at a snails pace. Do that on a janky bicycle...feels like you are flying.

[Geeto67]

Built it this weekend. Just used a Huffy Cranbrook beach cruiser from Wally World. No idea how fast I got it up to, but it's scary. Feels all sketchy when haulin' @$$ on it, ha ha. Somehow doing 20mph in a car feels like moving at a snails pace. Do that on a janky bicycle...feels like you are flying.

 

sounds about right.

 

I will say that most bicycles don't run a lot of rake or trail in the fork because they are bicycles so high speed stability is not a primary concern. Trail is most important to straight line stability and it is the distance between where the tire contacts the ground and the imaginary line of extending from the steering head to the ground. This explains it better: https://www.cycleworld.com/2015/05/22/cycle-world-tips-and-tricks-understanding-motorcycle-rake-and-trail

 

One of the reasons I like Schwinn springer forks is that you can use the suspension bolt to adjust the ride height and travel and thus adjust the rake and trail.

[RC K9]

That was an interesting read.

 

I remember thinking two things: 1.) I wish this thing has some sort of suspension. 2.) I think these wheels need balanced.

 

Regular cruising it feels alright. Let it rip and it just starts to feel all kinds of "i'm gonna fall apart and make you eat asphalt."

[Geeto67]

I remember thinking two things: 1.) I wish this thing has some sort of suspension. 2.) I think these wheels need balanced.

 

I think you are now experiencing the same thing that people did in the early 1900's when they were developing the first motorcycles out of bicycles, or again after WWII when people were developing motor bicycles to avoid tax and operating costs that led to the development of the moped. Too many improvements and at some point you are just building a small motorcycle or moped.

 

BTW, most states have laws that cover moped, and laws that cover bicycles but not really laws that cover home made motorized bicycles that don't meet the definition of a moped. Chances are, even with a gas motor, you are still not meeting the definition of a moped, but I would look it up just in case. Adding suspension and other things might push you into other categories.

 

Regular cruising it feels alright. Let it rip and it just starts to feel all kinds of "i'm gonna fall apart and make you eat asphalt."

 

Some of that may be from frame flex, some of it may be weight shift, and some of it may just be tire distortion from more rapid acceleration than the drive system is used to. Just keep an eye on things and check for frame cracks periodically.

[RC K9]

My dad took it for a quick spin around the neighborhood yesterday and some little turd dog came out to chase him and he hit the gas and outran it. It was pretty funny to watch.

[Red Beard]

You can try putting some weight in the tires something like sand mixture or bb's would help with centrifugally balancing the tire. That may help it feel more stable.

[bdhill]

chromoly or aluminum frame will be more rigid and stop speed wobbles as speeds increase.

[Geeto67]

You can try putting some weight in the tires something like sand mixture or bb's would help with centrifugally balancing the tire. That may help it feel more stable.

 

it also makes a neat swishing sound at low speed. However you can only do that on tubeless bicycle mag wheels

[Red Beard]

it also makes a neat swishing sound at low speed. However you can only do that on tubeless bicycle mag wheels

 

Yes and no lol, You can run them in an inner tube but it takes forever to get it all in there. We always used bb's because that is what we had. We had a 16 inch wand air nozzle for blowing off the mower deck growing up. If you took the tapered tip off the end, bb's fit into that perfectly. We would load that thing up one by one until we had a full tube and shoot them into the inner tube. Let the air back out and start over. It took forever but it did work lol. #bunchofkidswithnothingtodo lol