Can I use a power generator engine for a bicycle motor

GoldenMotor.com

Motor awesomeness

New Member
Nov 3, 2014
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Illinois
Hey guys, whats up, i got a question. Now remembering from my first post i would like to have a motorized bicycle thats chain drive and no welding as i live in a condo. Now i thought about it a bit more and since i dont have a 2 stroke engine, sprocket and chain, etc., i am thinking of using the engine from my 6.5 hp 3500 peak watt 4 stroke generator that has been unused for a few years. Im thinking use the generator motor and use a friction drive train. For the friction drive train im thinking of using a steel tube connected to the motor via a long bolt through the crankshaft, some sheet metal screws for the friction, a piece of steel secured to the bike frame using bolts cause im not gonna weld, and all this will be on the front wheel making a FWD setup. I should get to about 30-40 MPH with the correct gearing. What do you guys think and should what did i miss out on?
 

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Trey

$50 Cruiser
Jan 17, 2013
1,432
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Where cattle outnumber people 3 to 1.
I don't know about Illinois, but around here if you tuned up that generator and sold it, you'd get quite a few dollars.

You would have enough for a complete chain-drive motor kit, new bicycle, and then some.

These complete kits can easily be installed right in your condo with no welding and usually no power tools. Are you not aware of this? A quick look at the sponsors' sites would be quite helpful, then you could search this site with all your initial questions. Most have probably been answered:)

As far as the design you asked about, it may get a little hard to control with that 4-stroke up front. The majority of the friction drive rollers I've seen have been smooth. (both of these topics have been discussed here, these people are awesome)

Good luck, and please keep us informed.
 

Motor awesomeness

New Member
Nov 3, 2014
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Illinois
Yes Trey, I am aware but I don't have a ton of money and I can probably build it for less than 50 bucks as I have the engine, the homemade mount will probs be 20-30 bucks maybe less, the drive shaft will probs be 10 bucks or less as I plan to use a pretty good size shaft (about 2 inches for a 13 to 1 ratio) secured by a grade 8 bolt going through the crank and the shaft. Note that I will use the brake handle for the throttle which will be hooked up directly to the carb throttle plate so I'm goin ungoverned and the approx. top speed according to a calculator will be 20 MPH at 3500 rpm, about 30 MPH at 5000 rpm, and 35 MPH at 6000 rpm which is probably the highest I can get out of a u governed engine with the stock carb. Add in stuff like a bigger exhaust ( I might be able to custom make it), a bit of nitromethane mixed in the gas, bigger carb (I'm not sure the cc's), water injection, etc. will make that top speed go up past 40 MPH and nearing the 50 MPH barrier.
 

xseler

Well-Known Member
Apr 14, 2013
2,886
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OKC, OK
I always thought it would be a hoot to put one of those generators on a bicycle towed trailer and use it to power an AC motor attached to the pedal chain!
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
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northeastern Minnesota
First off, 6.5 hsp is a whole lot of motor requiring everything on the bike to come up to it in upgrades. Want to go fast? Better be able to stop fast, too. 40 mph on a motored bicycle is really fast. Fifty and you'd better know what you're doing. That's motorcycle speed.The frame itself needs to start out as a very strong one. The wheels need to be very strong as well. At speed everything becomes critical. Any time you're going non kit requires fabrication, often a lot of fabrication.

There are certain odds in your proposition, in my opinion. One is that it will be harder and more costly than you imagine. The other is that your chances of getting hurt are very good unless you can lower your speed expectations. Do it yourself projects are fun and what I like best and I don't want to dampen your enthusiasm, but I think you would do well to think this through some more and revise your plan. You can ride safely and still have a lot of fun getting where you want to go. Good luck to you.
SB
 

Motor awesomeness

New Member
Nov 3, 2014
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Illinois
I think ill be fine at that speed cause the bike has a aluminum frame and i got it from walmart for 140 bucks. And plus, this is the engine i only got, no other engine. I only got 100 bucks and a friction drive is cheapest as i already have some of the pieces needed. The bike also has suspension so the ride will be comfy. I plan to build over the summer when i have time cause i have high school to deal with.
 

boxcar

New Member
Dec 18, 2014
358
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Astoria OR
I'm with Silverbear on this one.
I'm a big proponent of home built machines but this idea is a bit dangerous IMHO.
You are going to strap a fairly heavy
6 hp motor to the front end of a bicycle.
Most front wheel scrub drives are very light for a reason.
The added weight changes the steering geometry in a bad way......
If you are going for a scrub ( friction ) drive,with that power plant I'd recommend a rear rack mounted system.
Safer , stronger , simpler to build with limited tools etc.
Have fun ...
 

Ludwig II

Well-Known Member
Jul 17, 2012
5,071
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UK
What about trading the big motor for a smaller one and some cash? That way you get an engine more suitable for the strength of the bike and it's parts, and some cash to buy any bits you hadn't allowed for that it turns out you do need.
 

xseler

Well-Known Member
Apr 14, 2013
2,886
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OKC, OK
This build has "Epic" written all over it ----- however, I don't which way the pendulum will swing.........

Good luck!


(I have placed a bet, though.....)
 

YesImLDS

Member
Jun 29, 2013
960
12
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Columbia, Missouri
It seems like you answered your own question. Almost everyone in the thread says this is a bad idea, but you are set on doing it... Then just do it and see what happens, if you do it right you shouldn't have any problems.
 

Motor awesomeness

New Member
Nov 3, 2014
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Illinois
They say it's a bad idea cause the motor is big and it's very heavy. True it is big but I'm not sure how big. I might try it this summer. If not, it's back to the drawing board
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
I know that you didn't hear what you wanted to hear, but you wanted some opinions. Among the issues for me was not the weight of the engine, but it's power. My suggestion would be to do a bunch of research here by reading people's build threads. If friction drive is your interest I'd suggest reading up on cannonball2 and his numerous build threads, several of which are friction drive and economical. A four stroke engine around 3 horsepower would be sweet for a friction drive. Lots of used ones of that size are around from snowblowers and all sorts of things. Watch Craigslist and you'll find your motor for not much money. Maybe sell your generator with motor on Craigslist, too. People here will be very willing to help you answer questions about your project. I hope you do it as it can be a lot of fun and practical transportation, too.
This is the time to do your homework, both in school and out... ha! Good luck.
SB
 

Motor awesomeness

New Member
Nov 3, 2014
42
0
0
Illinois
6.5 hp is a lot of power. I think the issue I would have is mounting the engine. Besides, bicycles are not designed to have a motor in the first place. I would love to have one. And once it's built, it will be my ride to school and around town. I just got to worry about cops, but only once it's built.
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
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Central Area of Texas
This build has "Epic" written all over it ----- however, I don't which way the pendulum will swing.........

Good luck!


(I have placed a bet, though.....)
Honestly Im thinking "epic" here is just a nice way of saying disaster.......

6.5HP 4 smoker on the front wheel is a bad bad idea.....
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
You say you have $100 to spend, you can probably get another $100 easily for the generator then you have $200 to spend, and for about $130 you can get a 2 stroke kit that will basically have everything you need to motorize a bike that can use an inframe CG kit.

even if you need a special front engine mount or a couple other small items youll still have enough money to cover it.

The way you planning this build is you'll wreck a generator and probably the bike when its all said and done and you'll basically have nothing but loss of funds and hopefully nothing more than minor injuries to show for all of it.

Not hating on your idea completely here, but if you cant do something that will be safe and logical, I recommend holding off until you can.

just my $.02
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
They say it's a bad idea cause the motor is big and it's very heavy. True it is big but I'm not sure how big. I might try it this summer. If not, it's back to the drawing board
i have a couple of the gx200 clones like you're thinking of using and i can tell you for a fact that they are way to heavy to be making a front wheel friction drive out of, and the power and torque of these engine will literally shred a bike tire in just a few rides as a friction drive, way to much power and way to much weight.
 

fatdaddy

New Member
May 4, 2011
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San Jose, Ca.
ALRIGHT SON, C'mon in, sit down and LISTEN!!! I may be the oldest old fart of all the old farts here. And there's a reason I'm old. When someone said to me "I tried that and almost died". I LISTENED. Me, and most of the guys who got back to you on this have been doing this for a long time. I personally have well over 100 bike builds behind me. Some of these guys have even more. SO, THEY KNOW OF WHAT THEY SPEAK. You should really start listening. If ya dont wanna take advice, WHY are ya here?
engine is too heavy, too much power and will shread yer tire, throw yer steering control WAY OFF, ect, ect.
NOBODY can help someone that dont listen
Yeah,I wish I was 16 again too.LOL
fatdaddy.usflg

A rear mount would be bettercvlt1 TRUST ME!!!
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
ALRIGHT SON, C'mon in, sit down and LISTEN!!! I may be the oldest old fart of all the old farts here. And there's a reason I'm old. When someone said to me "I tried that and almost died". I LISTENED. Me, and most of the guys who got back to you on this have been doing this for a long time. I personally have well over 100 bike builds behind me. Some of these guys have even more. SO, THEY KNOW OF WHAT THEY SPEAK. You should really start listening. If ya dont wanna take advice, WHY are ya here?
engine is too heavy, too much power and will shread yer tire, throw yer steering control WAY OFF, ect, ect.
NOBODY can help someone that dont listen
Yeah,I wish I was 16 again too.LOL
fatdaddy.usflg

A rear mount would be bettercvlt1 TRUST ME!!!
Mucho Ditto sir........