If you’re ready to move on to something more challenging than a bicycle for yourself or your son or daughter, then a mini bike could be a perfect upgrade.1 Building one is not as hard or as expensive as you may think, so it’s a great DIY project if you’re looking for something constructive to do in your spare time or simply want to try your hand at building a fully functional mini bike.
The best advice for novice mini-bike builders is to keep it simple.
1. Basic Set of Tools
You don’t have to be a master mechanic or even have a master mechanic’s toolbox. If you have a basic set of garage-kept tools to do regular maintenance around the house or on your vehicle, you should be fine.2
You’ll need wrenches, sockets and ratchets with extensions, at least a flathead and Phillips screwdriver, mallet hammer, and a can of WD-40 (spray grease). These tools are so common that if you don’t have them, I’m pretty sure one of your neighbors will, and if not, your neighborhood hardware store will.
The frame will be the nucleus of your mini bike; everything in one way or another will be attached to this. Some people like to fabricate their own or fabricate one from a bicycle frame.3 Unless you have fabricating and welding experience, this is not a good idea.4 Remember, you want the rider to be safe on this bike.
If you look around the Internet, you should be able to find one fairly cheap, possible in your neighborhood. Craigslist is a great place to start. If you strike out there or don’t feel comfortable buying from someone you don’t know, there are places that sell mini bike frames for good prices.
3. A Dirt Bike Engine Kit
If you’re a novice builder, you probably don’t have spare parts, bolts, washers, and tons of odds and ends lying around in your garage as a mechanic would. Buying a kit is the best way to make sure you have everything you need to get the drivetrain portion of the mini bike running. It could take weeks to piece together every portion of the drivetrain with no guarantee that everything will line properly.
There is a great all-in-one kit on Amazon that includes everything you will need, from the engine and gas tank to the throttle cable, sprockets, and muffler. All you really need to get the drivetrain to run is the ability to read directions, basics tools, gasoline, and oil.
If you or your kids start to grow out of the performance that the engine makes, you can always change gears or even bolt on a bigger engine quite easily, but the Amazon kit is great for first-time builders and riders.
In the process of putting all these parts together, it’s always best to lubricate all bolts, nuts, screws, washers, and metal to metal objects (WD-40).5 And as always, make sure everything gets tightened down well, but you don’t have to tighten them down with massive, brute strength. You don’t want to break a bolt off. Bolts are made to be snug tight, but not Incredible Hulk tight.
4. Tire and Wheels
Now it’s time to get something for your mini bike to ride on. For this, you can try to save a little money and shop around for a good deal from a private owner, or you can go through a place like GoPowerSport.com to get a pair of wheels and tires. Your biggest concern here will be knowing what size to buy. If you buy a pair of wheels and tires that are too wide, they won’t fit between the frame forks. If you go with a set that is too tall, the wheels and tires won’t fit under the frame properly.
If you have a good idea of what you’re looking for, then getting a little creative and saving some money is great. If you don’t, take some measurements and talk to someone who can point you in the right direction. Mini bikes are pretty light, so if you can, take the bike with you when you go to buy wheels and tires. This ensures a good fit front and back. Basically, if you go with a basic frame, then you will want to go with a basic set of mini bike wheels and tires.
For the front axle, you won’t need much more than a long bolt, nut, and some washers, which may come with the front wheel and tire if you go to a motorbike shop of some sort. For the rear wheel, tire, and assembly, as long as you have a universal sprocket, which the Amazon kit comes with, everything should line up properly.
Important: Lining up the chain from the engine to the rear sprocket is extremely important. First, you want to make sure the chain runs straight-back from the engine to the rear sprocket (straight-back). It should already, but if it needs a centimeter or two of an adjustment, you should have the play to make that happen. Also, the golden rule with chain slack adjustment is the “1-finger rule.” That is how tight you want your chain to be. There should be enough slack in the chain to either move about one finger up or one finger down in distance.6
Fenders are optional. Technically you don’t need them to ride a mini bike, but they are nice to have to keep mud, dirt, and rocks from flying up at you. This is another place where basic is good. If you have a basic frame and a basic set of tires, then a basic set of fenders will do just fine.
Unless you plan on taking your mini bike to mini bike shows, I would go with the cheapest fenders you can find. A plastic set can always be painted any color you want, and as long as they keep the ground debris down, they’re doing their job. This is also an easy place where you can get creative and save money. These aren’t precision parts you have to worry about working perfectly, so if you can make them on your own, I say go for it.
Here is another place you can use your imagination and save money. As long as you have a seat that bolts down tight to the frame and is safe and comfortable for the rider, anything goes here. I’ve seen people take seats off old Huffy bicycles and make them work quite proficiently. But if you want a new one, there are plenty of places you can buy them to fit any rider.
7. Mini Bike Brake Kits
Not all mini bikes have brakes because they don’t go that fast and the clutch tends to do the braking for them. But if you want braking capabilities, there is an inexpensive, easy-install brake kit right here. Make sure when running both the brake and the throttle cables that they have plenty of room for movement as they will need some slack when you turn the front wheel back and forth. But at the same time, do not have the cables dangling close to any in-motion parts. If you need some extra guides for the cables, zip-ties work perfectly.
8. Check Everything and Test Ride
Before you start your mini bike up, you need to fill up with the right oil and gas to the standards of the engine company. Then you will want to start the mini bike up and let it run a little bit. Take a walk around the bike while it’s running and make sure it’s holding up well to the rattling of the engine. Make sure all the bolts are staying tight and the only funky noise you hear comes out of the muffler.
Once you have determined that everything is safe to drive, then you’re ready to take it for a test ride.
Stick to the Basics
As you’ll see in this video, if you piece your first mini bike build together with parts from here and parts from there, you will run into all kinds of problems. That’s fine if you’ve been down that road of customizing and dealing with problem-solving in your garage many times before, but if you haven’t and still want to get a mini bike put together safely, stick to the basics.
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- Steinmeyer K. Badass Mini Bike Kits: How to Get Your Kid Started Early. Badasshelmetstore.com. Published July 26, 2016. Accessed April 22, 2021.
- Vaglica S. Must Have Tools in Your Home Tool Kit. Thisoldhouse.com. Accessed April 22, 2021.
- N J. How to Make a Homemade Minibike. Howtoadult.com. Published April 18, 2017. Accessed April 22, 2021.
- Patrisso G. Steel Bike Frame Welding & Fabrication – Is this a lost art? Bakersgas.com. Accessed April 22, 2021.
- Mahoney P. The Importance of Using Thread Lubricants in Bolted Connections. Pumpsandsystems.com. Published September 4, 2018. Accessed April 22, 2021.
- Lindemann M. How to Check and Adjust Your Motorcycle’s Chain. Cycleworld.com. Published August 28, 2015. Accessed April 22, 2021.