Introduction: How to Make the Cheapest Motorbike Ever!

 I have started makeing this instructable since I cant find anything nice on how to make a cheap motor bike. so here it is (my cost was ONLY $30) but i already had the motor and some other stuff. you will need to read through this whole instructable before you start also this is my second instructable so i may have forgoten something so just leave a comment. you should reach speeds up to 30mph depending on weight and ratio and the size of the engine.
  you will also want to check your local laws to make sure it is legal! and stuff

Step 1: Materials!

Picture of Materials!

in this project you will need,
1. a bike of any size
2. a weed eater motor ( I used a 25cc craftsman)3. angle aluminum (hardware store)
4. a 6" long 5/8" threaded bar with 2 matching nuts5. a bike peg

Step 2: Prepare the Motor

Picture of Prepare the Motor

it is better if the motor you are using doesn't have a clutch if it does then remove it. now take off all the plastic on the motor that doesn't need to be there mainly just over the flywheel. then if your motor doesn't have a clutch remove the cover over the crank shaft, not the crank case! it will take lots of effort, it helps to use a hammer. then take your bike peg and see if it fits the threading if it does your lucky, if it doesn't take the cover to a machine shop and have it threaded to fit the peg this is what i had to do

Step 3: Prepare the Bike

Picture of Prepare the Bike

get the bolt and mount it to the brake cross section with two u bolts you will not have use of the rear brake on this bike so be carefull

Step 4: Mount the Motor

Picture of Mount the Motor

you are going to want to mount the motor on a piece of angle aluminum and a tension spring to keep it on the tire i am pretty sure you can figure it out based on the photos but if not just comment.

Step 5: Set Up Electonics and Throttle

Picture of Set Up Electonics and Throttle

set up the kill switch on the handle bars i just went and used the kill switch from the motor and extended it with some normal electrical wire from home depot. the throttle is very tedious to connect and is different on every motor, so your on your own then but use the rear brake lever for and cable

Step 6: Finally Done, Lets Ride!

Picture of Finally Done, Lets Ride!

now your done go impress everyone thats has been doubting you to start you just peddle and give it some throttle and keep peddleing when you are going slow just to keep the engine from stalling. please comment and rate! my motor just died so i am replacing it then i will post a video of it working.


Infinite Gam3r (author)2017-09-10

Hey dude thanks for making this how-to page because me and my bro really want to make a weed eater bike and I think this will be extremely helpful. Also you did a good job at making your bike!

JohnJ350 (author)2017-04-23

Just wanted to give you a 2 thumbs up,pretty awsome little dude,,about how much did you spend?ill be atempting my.own bassed on gour instructions in about a week or so.

brads4 (author)2015-03-27

brads4. u can email me at or call me at 580-280-5411. facebook has made my account temporarily unavailable. wonder whats up with that!!!!

bdaman4b (author)brads42017-02-13

Hey buddy i am attempting to try thiz myself real soon if i have any delima may i give you a would be greatly appreciated.

DakotaA1 (author)2015-02-13

are you suppose to take the clutch off cause every vedio i watched they say to take the clutch off.And some say to use a clutch

I tried to use a weedwacker clutch and it ware out after a few days. Not worth the trouble

ya mostly craftsman clutches are horrible its like you hit too big of a peice of grass and the clutch fails

brads4 (author)2015-03-27

i can't believe u took off the clutch when u could have welded the footpeg to the clutch drum eliminating the need for a tensioner. also the engine l bracket could have been bolted to the seat seat post other than that u did ok. i had a schwinn (sp) english racer when i was 11. i bolted an 80cc westbend 2 stroke to it and direct drove an 8 tooth sprocket to a 40 tooth i had brazed to the rear wheel spokes. u do the math. i was doing about 120 when i eased by the 1st baptist on US 183 in snyder, ok. the nightwatchmen was drunk and asleep at the wheel of his wagon. seems to me that jess dunn and i lifted two motors from a warehouse on s. najavoe in altus. he took the clinton 50cc. jess was not too damn bright.

patd20017 (author)brads42016-08-17

hey if you can give me a text to I was wondering if you can build one and ill pay you or if someone else would for a price


FatdaddyS (author)patd200172016-08-20

My father makes homemade motorbikes
he said he is willing to make yu won if you are interested

miles315 (author)2016-08-11

Hi, I was wondering how you connect the peg to the motor? Do you need to weld???

Omark42 (author)2016-08-11

how do you put the peg on the motor

R1SK (author)2016-07-19

What is the best style/tread tire to use with this design?

GageJ (author)2015-11-18

I found a 33cc leaf blower motor laying around. Anyone think it'll work well? I mean, surely it'd be faster than a 25cc?

spencdood (author)GageJ2016-07-02

yea it may go faster

owloscar made it! (author)2016-01-23

I made one based off this instructable but i attached the chain to the engine to get more power out of it but i did use an angle grinder and welder

Creator0001 (author)owloscar2016-05-30

how did you exactly do that?

spencdood (author)Creator00012016-07-02

all you have to do is bolt the engine to the water bottle holder, and attach All the gears. i know because i tried it, and its hard to do because i haven't finished it.

DevM8 (author)2016-07-02

great work. looks easy to run.

I am impressed by low power motors/engines. its just the fuel economy that doesn't seem to work.

really good video


TrollZen (author)2016-04-13

im working on something like this myself in my workshop

Velixare (author)2015-10-21

Another question, is there a way to modify it so you still have the back brakes?

Velixare (author)2015-10-21

Would a 18cc engine work, i realize if it does it won't be near as powerful. Just asking if it would still work or not?

BobbyT3 (author)2015-08-06

Much easier to just use 2 sprockets and make it a chain drive bike. I used a regular buke chain to pedal it and start it and a thick chain from a transfer case of an f150 plus a 10$ snowmobile sprocket forbthe motor drive

RahY1 (author)2015-07-03

Where can I get the 25cc weed eater and for how much

amalik22 (author)2014-07-18

My bike does not have a rear brake assembly at all. I took it off some time ago as it was rusted and beyond use. How can I use throttle then?

worked fine for me

ChaslasherH (author)2015-04-06

hi i am trying to make this and was curious what brand is the motor you use

manman.jonesii (author)2014-08-24

i would pay you to build me one

jwatkins9 (author)2014-07-17

I just got a weed eater just for this, the front brake is an issue, i have the scars to show not to use it without the back brake, my front brake is broken so i am connecting the clutch on mine to it so i don't have ti shut off the engine to stop.

Great job though!

csheehy-holbrook (author)2014-05-03

how long of angle iron

Jojocircles (author)2013-02-02

Could you explain how to take the motor out of the weed eater? my father and I are gonna try to do this project thanx!

willnate (author)Jojocircles2014-04-08

you just basically unscrew and unbolt everything until you have just the engine

cshwenie (author)2014-01-20

Hey BIGHAIRYDUDE, I have a question. My dad and I built one of these but we used a turnbuckle for the tension. When I apply a very small amount of pressure to the tire, the engine sounds like it is bogging and can't push. But when I take a tiny bit of tension off, it works fine except there is not enough tension to keep the peg from slipping on the tire. Can you help?

celliott96 (author)2013-07-18

Hey, I have almost the exact same engine as you. Craftsman 25cc. Anyways, when I was trying to mount the angled aluminum beam onto the engine, the flywheel is in the way of the beam. Should I cut the beam so it doesn't touch the flywheel or should I just try to mount the beam somewhere else on the engine?

Jojocircles (author)2013-02-02

Can someone help me

Jojocircles (author)2013-02-01

Is the threaded twisty bar thingy needed? Btw Great invention

chiefs543 (author)2012-04-30

How do you put the peg on the clutch shaft? Can you u just thread it with a tap and die? Would it work if you just mounted the clutch shaft against the wheel without the peg on it? Also, does it have to be adjustable tension or cant the engine be mounted firmly against the wheel?

BIGHAIRYDUDE (author)chiefs5432012-05-03

you can thread it yes it will not work shaft against the wheel but it would work if you used the clutch bell if you dont know what im talkin about it doesn't matter, and the engine can be mounted firm or adjustable its all preference

chiefs543 (author)BIGHAIRYDUDE2012-05-04

Thanks. This helped a lot

tobychan (author)2012-04-02

That's awesome! I have a 49cc strimmer engine I've been wondering what to power. Mine has a centrifugal clutch so I think i'll keep that on. But i'll let you know how I get on with it and post an Instructable, giving all the credit for the idea to you of course. :D

You213 (author)2012-02-06

It seems like the motor would be floppy and stuff becasue there is nothing really holding it on... How stable is it?

BIGHAIRYDUDE (author)You2132012-02-10

holds very well with steel the aluminum bends but it holds up good i go over bumps hills and everything and it doesn't complain

phynicfirebird (author)2011-06-26

I have a quick question for anyone that wants to answer. When you stop at a stop sign do you have to turn off the engine or can u just use your brakes?

in this you have to stop the engine

Kiteman (author)2011-05-15

He's increasing the power, and restricting himself to front brakes only...

Anybody want to start a book on how long before he face-plants at speed?

_-MacGyver-_ (author)Kiteman2011-05-23

Agreed, Its a great concept, but losing your back breaks and using only the front ones is a recipe for disaster. I have had a few nasty knocks because of my front breaks. I finally just ripped them off my bike

CybergothiChe (author)Kiteman2011-05-16

lol, face-plant, because it's a weed eater

BIGHAIRYDUDE (author)Kiteman2011-05-15

ha front brake kind of sucks so the real danger is not being able to stop quick enough

rimar2000 (author)2011-05-15

Very good work, BIGHAIRYDUDE, congratulations.

Beware of the front brake, it can throw you over the bike. I say this for own experience! That fly is funny but dangerous.

BIGHAIRYDUDE (author)rimar20002011-05-15

hey some of you guys might notice this is a copy of my original bike but for some reason that instructable deleted itself so i still had the pdf so i copied it over so its really the same bike as before

About This Instructable




Bio: i am in school and i like to build things i prefer everything that has two wheels and most of my projects require the use ... More »
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