Honda Motorized Bicycle




About: I live in Portland, I go to school at PCC, and work on projects in my spare time. I'm studying Renewable Energy or Engineer haven't decided yet. I have a motorized bicycle that is my pride and joy. I love tr...

Before I start I would like to press a major safety issue. Please always wear a helmet. I recently got into an accident and it would have been much worse without a helmet. WEAR A HELMET! The damage can be seen in my other instructables here.

Okay now to the stuff you came to read and see. I completed this project with a friends help way before I started making instructables. So there is a little bit of step-by-step but not much. Even if there was the build is very subjective to the bicycle on hand. We built this bicycle on a decent budget without breaking the bank on a $660 Golden Eagle kit. In total I think it was about $575 to have a complete fully upgraded motorized bicycle which is still less than the kit or buying those silly Chinese kits. The bicycle I have is a Walmart Schwinn, the reason for it was I wanted nice accessories over a nice frame. The bike is heavy and a lighter frame would help but doesn't stop it from reaching a top speed of 30mph on a flat. I cruise at a comfortable speed of 20 mph I don't believe in W.O.T. (wide open throttle) an engine for more than 30 seconds and like keeping it at about 2/4 throttle. Anyways to the shopping list and what it cost me.

To start the shopping list this is what I bought:

  • $114 worth of parts from Golden Eagle (which is the total cost of the next three items)
  • The drive ring $50
  • Sprocket #12 $32,
  • Bicycle $?
  • Belt $32.
  • Honda GX31 with a centrifugal clutch about $80 on Ebay used.
  • Pieces of aluminum laying around that got cut to length and fitted to the bicycle. $?
  • The belt tentioner was made from a short piece of aluminum and two bearing. $?
  • Thumb throttle from Staton $16

In total before upgrades it only costed roughly $280 to have a motorized bicycle. But as described in my last part of this instructables you have to upgrade some parts like the tires, rims and other equipment you want on the bicycle. I will say it was a tricky to build because you have to measure twice and cut once. I already built it so it's hard to describe how it was built and put together.

Please leave a comment if you have any questions.

Step 1: Why This Motorized Setup?

First off there is a dizzying array of motorized bicycles and different ways of doing it. I'm not claiming this is the best motorized bicycle but, it's better than most. The most common is the "80cc" Chinese kits that are utterly cheap and people (like me) will and have wasted time and money on them. I could go off on a tangent about them but I wont so moving on. The next one is friction drive which involves a metal rod that sits on the tire. The problem is they are useless when it rains and eats your tire alive. Then there is Staton with it's very own confusing selection of engine kits. Finally we come to the best option Golden Eagle, with it you can go three ways with the design. First is buying the kit flat out for $660 which is the quick and easy way of doing it. The second is buying their mount kit which is great if you have a mini 2 stroke or four laying around. The last one is what I did, by buying some parts from their site and building it from scratch.

Step 2: The Motor

You can use a Honda GX35 but they cost $250 brand new if you want. On this I used a Honda GX31, it's a 31cc engine, 4 stroke, quiet running engine, and about 150 mpg. Golden eagle explains why a four stroke is great to use towards the bottom of the page here. Be aware when buying a GX31 that there is a tiller version and a trimmer version both will work but the trimmer style air cleaner works the best. The engine can go up grades but can't go up anything major without pedal help (it's a 31cc engine it can't work miracles). On Golden Eagle you can get a #11 high gear for hilly terrain, #12 the all a round gear, #13 the highway gear for flat terrain. I went with the number #12. The gear size will also depend on the size of the engine you use.

Step 3: The Motor Support

The way you build the support will solely depend on the bicycle you have. It must have a solid axle no quick releases! Why? The aluminum plates get bolted right on to the axle. There needs to be at least 3 points of contact for the frame. Two of them must be on the axle and one needs to connect to the frame to prevent the engine from twisting. The supports are made out of aluminum because it is lighter and doesn't rust. You can use steel just be a little heaver and you could weld instead of bolting it up. The aluminum was cut using a simple band saw just be sure to use cutting oil. Then edges where rounded off with a sander (makes it look professional).

Step 4: Bicycle Upgrades

In this step show you how to make a bicycle ready to accept it's new motor counterpart. I am creating this because there isn't much information on the bicycle upgrades when adding a motor. More times then not the standard bicycle rim and wheels can't take the abuse. I will present the things I had to do to upgrade in a few steps so hopefully you wont make the same mistakes/discoveries as I did.

The first items to go on my Schwinn are the cheap tires. Please I beg of you!!! Go to a bicycle shop (local preferably) and get wonderful flat resistant tires they are well worth the money especially on a motorized bicycle. I got Bontrager tires and they are amazing I have never had to worry about flats. The rim had to be replace after spoke after spoke broke. Tongue twister! So I decided on a custom rim from Sugars in Portland, OR and had one handmade they even soldered the spokes. I know that sounds outrageously expensive it's not it is well worth the money considering the cost of spokes and truing the wheel. Also I have a horn for special events and or to warn cars, bikes, and pedestrians that get in my way hehehehe.

  • Bontrager flat resistant tires $45 per tire ·
  • Upgraded custom rear rim $160 ·
  • (A shout out to Sugars customs bicycle rims in Portland, OR for doing a wonderful job!) ·
  • Horn (optional) $10 to $60 ·
  • If you don't have fenders I recommend them
  • Always have a bright bicycle light front and rear!
  • A well fitting helmet it can save your life trust me on that!

Step 5: Upgraded!

Here are the upgrades on the motorized bicycle. These upgrades in my opinion are very necessary to have a reliable commuter motor bike. I've gone at least 400 miles so far without a lick of mechanical trouble. Hope this helps those of you thinking about a motorized bicycle design.

Feel welcome to comment or ask questions below



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    90 Discussions


    4 years ago on Introduction

    Helmets suck. I quit riding motorcycles because of helmet laws. If you want to be safe, stay off of 2-wheelers. Not to mention that bike helmets are useless in a serious crash.

    19 replies

    I always wore a helmet while riding my various motorcycles. I had my first accident after a couple of years and because I was wearing a helmet I simply walked away. Limped I guess would be more accurate. The helmet had a huge gouge down the side, I would have died instantly without it. Instead, using the helmet enabled me to have another 20 years of good times with good people on motorcycles. The statistics heavily favor wearing a helmet, without one riders often die way too young in accidents they could have easily survived.

    There are helmet laws for the same reason there are seatbelt laws and
    mandatory insurance laws and dui laws: The insurance lobby. Such laws
    are couched in all sorts of good-for-you language, but the truth is that
    the lobby that gets them passed is the insurance lobby. IMHO, it is
    for the individual to decide such things, and not the government. But then, I'm old enough to remember when there weren't any of them.


    But that is their business. I rode without a skid lid for 5 or 6 years back in the late 60's and early 70's, had a couple of mishaps and survived. It adds spice.

    Nothing in life is so exhilarating as to be shot at without result.

    Winston Churchill


    As it is your business. It is your choice not using a helmet, just remember that very choice could leave you as a vegetable in a hospital or even dead. I understand that it was for the "thrills" but the point of the matter here is that life is so precious how could any normal person rationalize the shortening of their life by not wearing something as simple as... yes, a helmet or a seat belt, or not drinking and driving. Something I have learned is it is not worth the risk. I want to have a full and healthy life. I want to be able to live to see the day I graduate school, marry that special someone, and watch my children go off to college. If it means wearing a silly helmet and "playing it safe" than so be it.

    Absolutely true so why rush tom the end before you've lived?

    We can usually live longer and have more enjoyment from life by taking reasonable precautions. It would be foolish for me to argue that enjoying life these last 40 years thanks to a reasonable precaution rather than dying young over something as small as making my stand on over the helmet laws is somehow an affront to freedom.

    Ghost Wolfmarcintosh

    Reply 4 years ago on Introduction

    Hahahahaha I love it! Here's what we call bicyclists that go the wrong way. Salmoning. Get it? Going the wrong way of river is what a salmon's an Oregon thing :P


    The main point is that helmets are there to prevent injury. In my case I avoided a cracked skull and a concussion thanks to the humble helmet. In serous accidents sure it is questionable. Same thing with air bags, in a serous crash airbags don't always save you but it's still mandatory to have them.

    RonT59Ghost Wolf

    Reply 1 year ago

    Can anyone direct me to the helmet law forum?

    kdavey1Ghost Wolf

    Reply 4 years ago on Introduction

    Air bags saved me in a head on collision, but almost killed me with what they used to keep it from sticking to itself. Mine used talc which I'm extremely allergic to. Would've been nice if that fact was included in the owners manual.

    Hey Snidely70448, I wear a Helmet when I ride, I buckle my seatbelt when I drive and I call a cab when I've been out drinking, not because it's the law, because it's just plain and simple common sense! Anyone who thinks differently must be a organ donor wannabe or a complete moron.

    We have DUI laws because alcohol figures in the death and permanent injury of more people than wars. We have mandatory insurance laws so that you are financially responsible for your behavior when you total my car and are the party at fault. There were laws against causing damages and injuries to people while drunk on horseback.

    There are lots of people out there, I've had relatives that would be included in that list, that would love to be essentially free of taking personal responsibility for their actions.

    There is no society that has citizens without responsibilities. We can enjoy the wide span of freedoms we have, or we can complain that things like speed laws or DUI's crush our spirit.


    Reply 4 years ago

    As long as the law is going to require life saving care not be denied regardless of the fault/cause of the injury or the likelihood of the individual* paying the bill, they are also going to require doing simple things to minimize injury.

    * Notice I say individual and not victim. I'm not sure who the victim is anymore.


    Reply 4 years ago on Introduction

    I have long hair and after riding in Westport, CT for an hour with my helmet hanging off my elbow, I can honestly say, "helmets are a godsend if you don't want to comb out knots for 2 hours." : )

    I tried - honestly, but I came up with too many ways that a helmet can help. I even picked bugs out of my teeth. I'll never go back. If I'm on 2 wheels, I wear a helmet. If I'm going over 40, I wear a full face.

    And I've NEVER ridden while under the influence of anything. That's just common sense.


    When you're a college student I need a cheap form of transport. Although I would rather have a car it's much safer.


    There are helmet laws for the same reason there are seatbelt laws and mandatory insurance laws and dui laws: The insurance lobby. Such laws are couched in all sorts of good-for-you language, but the truth is that the lobby that gets them passed is the insurance lobby. IMHO, it is for the individual to decide such things, and not the government.