Get Ahead Of The Game: How To Put A Motor On A Bike Step By Step

By Amy L

Putting a motor on your old bike is a great step to giving you more speed and your bicycle and new lease of life.

I used to snub my nose up at everyone who wanted to have a motor on their bike. Why would you do that? Well, one day I tried a bicycle with a motor and I found out exactly why you would!

A little kit can transform your bike with a motor. Want to know how?

In this how to put a motor on a bike step by step guide, we’ll be looking at:

  • The steps needed to mount and install a motor to a bike
  • FAQs
  • Final Thoughts

What You’ll Need:

  • Bike motor kit
  • Measuring instruments for petrol and oil
  • Spray lubricant (WD40 is good)
  • Zip ties
  • Starter fluid
  • Pliers
  • Screwdriver
  • Wrench

Step 1: Bike And Motor Compatibility

Before you get into installing your motor, you will need to make sure everything is compatible. The engine will need to slot into and mount your bike frame comfortably.

Don’t forget to leave enough space for the motor to breathe. An engine that can’t breathe will struggle so even though it may be tempting to go for a more powerful motor, you won’t actually get the best out of it if it’s not breathing properly.

Think of it like people, if you can’t breathe, you can’t perform as well, can you?

You will also need to give some consideration as to how heavy the motor is and how the bike frame can stand up to that. Ensure your bike can take the motor comfortably. This will include the rear wheel as this will be taking some of the pressure.

Step 2: Install The Sprocket & Removal Of Rear Wheel

First off, always use a new engine sprocket.

Why?

A new sprocket is going to be compatible and fit with your new engine parts. It’s peace of mind that all the parts are best suited to each other.

Some riders choose to use the same sprocket on the basis that it will provide low torque. I get that thinking but it’s best to do the job properly and use what works with the kit and your bicycle. In this case – a new sprocket!

Grab your spanner and remove the two nuts on the rear wheel.

Now you will be able to remove the bike chain. This will enable you to be able to completely remove the back wheel. Got it?

On either side of the tire, you should put a rubber bush. From there, the sprocket screws can go inside.

Behind those screws, you should put in a steel washer. This will allow you to remove each screw easily, should you ever need to.

Now you can tighten up the screws and nut and reattach the rear wheel.

Step 3: Fit The Engine Kit

Despite how daunting this may sound, it’s actually not all that complicated…honest 🙂

There will be a mounting bracket included in the conversion kits. Use this to fit and install the motor to the bike frame. With most kits, the engine will be held in with a nut or two so it’s just a case of screwing it in place.

Step 4: Install The Spark Plug

A spark plug is super simple to install, it’s a twist-in plug job – just like a lightbulb, it can be done in no time!

The purpose of a spark plug is to create a spark with the petrol and so causing your engine to start up. Without a spark plug, nothing will happen and you’re bike will be a bicycle that requires you to pedal – pretty sad thought, huh?

They’re small but mighty!

Step 5: Install The Clutch

Think of the clutch as a handbrake.

A lot of cyclists choose to fit and mount the clutch close to the left handle. It’s used to engage/disengage the engine so easy access is a smart move and will save time.

If that works for you, first remove the left brake lever in exchange for the clutch.

The other end of the wire can go into the bar of the motor.

Take your screwdriver and tighten the wire.

Tip – This is a task you’re going to have to do relatively frequently. Using the clutch will cause the screw to loosen. Keep an eye on it!

Now to test it out!

Hold down the clutch.

What you should see is that the long bar will move inside and when you release the clutch, it should go back into its straight position.

If that’s the case…nice job!

Step 6: Fit The Chain

You will need to put the chain between the engine shaft sprocket and the bikes sprocket.

There will be a motor cover, which you will need to open.

When you come to release the chain then you will have to remove the master link (I explain how to do this in this guide – you’re welcome 😉 ).

An end of the chain should be fitted into the sprocket. Once you have several links in there, it’s time to turn the engine gear to work things around. For this, you will likely need a ratchet.

So the other end of the chain goes onto the other sprocket that will be in the rear wheel. When you mount the chain in place, you just need to reconnect it with the master link again.

All of this should mean that your chain is put back together again!

Step 7: Set The Throttle Up

On the right hand of the handlebars, you can mount and install the accelerator. This will need to be connected to the carburetor.

What’s a carburetor? I hear you ask!…

Step 8: Installing The Carburetor

This will need to be installed into the engine frame.

As this location will vary based on which motor bike kit you opted for, it is best to look at the manufacturer’s instructions for an accurate position!

Step 9: Install The Petrol Tank

Where the mounting bracket is you should look to install the petrol tank. Commonly it fits onto the straight bar of the bike.

Once it is installed, using the tube that will come with the motor bike kit, connect the tank up to the carburetor.

Step 10: Muffler Install

A muffler acts as a kind of silencer. You can (and should) mount and install it on the engine exhaust. There will be bolts included in the kits for this.

That’s it! Now you can speed around on your motorized bicycle!

For a more visual guide, you can check out this.

Frequently Asked Questions

If you’re considering purchasing one of the many electric motor conversion kits, you probably have some questions!

I’m not going to lie, you will need to have some knowledge around how a motorized bike works and a few basic tools.

Without the experience then you could run into problems, which nobody wants. Not to mention that it’s a dangerous undertaking, not only for you but others around you.

Do I Need A Mechanic For My Motorized Bike?

As I said in the introduction if you know what you’re doing with a set of tools, you’re capable of following directions, and a bit of time, then you should have the means to put a bicycle engine together.

Having said that, it does take a degree of expertise and if you’re in doubt, it may be wise to get an experience hand to assist you.

It’s not the quickest job and will take time, even for a mechanic, conversion kits will take several hours to fit and install.

A good idea is to study the kits you are interested in and make sure you have the kind of skill needed to complete the job.

Another thing you can do is to take a look online, there are always reviews of people saying how they got fitting the motors. This can give you a good indication of the difficulty level.

Am I Legally Allowed A Motorized Bike?

Alright, so this is where things can get a little more complicated!

Certain kits will be legal and others won’t. It will also depend on your state too.

There are a number of factors, including power source and the size of the motor.

It’s difficult to categorically say whether or not you can legally ride a motorized bike so I would highly recommend you spend time checking with your local authority.

What Motor Do I Need For My Motorized Bike?

Another tricky question!

Let’s break it down into steps.

1 . Consider where you will be using your bike and how frequently you’ll be riding.

If the answer is that you won’t be using the bike too often then the need for a motor will a big fuel tank isn’t there. Don’t get something you don’t need. It will add more weight and expense.

2 . Budget

First thing, a bicycle motor kit can vary in price hugely so you will need to have a budget in mind.

If it can be avoided, I would advise against going for the lowest-priced motor.

Opting for a well-known, well-respected brand is always a good move. You will get a full warranty and usually, there will be help on hand if you ever need it.

3 . 2 Stroke Engine vs 4 Stroke Engine

A bike motor will have either two or four strokes.

All this means is that with a 2 stroke engine the motor will have a cycle of two strokes moving up and down each.

With a 4 stroke engine, the cycle will go four times. Pretty simple, right?

I’d recommend a 4 stroke for your bike if that’s possible to mount. A 2 stroke will produce more torque as it uses a mixture of gas and oil. A big downside is that they can be noisy and not as good for the environment.

For a 2 Stroke build, you can look here!

4 . Types Of Kits

There is no shortage when it comes to choosing a bicycle kit, knowing what kind is a bit more challenging!

You will need to weigh up a number of factors before you make the leap and purchase a bike kit. First, think about your specific criteria, this will include things like your body mass, the types of terrains you will be riding in (will there be a hill or two, and much leg power will you need?). Obviously, the max speed of the bike is another consideration for many.

Lightweight riders can choose a motor on their bicycle that is smaller, in the 50cc range. This size motor is usually the kind that is ideal in this scenario.

If you weigh more than 200lbs then the motor bike kit you will need will have to have more power in order to get the best out of the bicycle kit.

Don’t underestimate how much of an impact terrain can have on this type of kit. The engines will need to be able to deal with inclines and carry you and so if you live in an area with these kinds of hills, a bigger motor could be the way to go.

Can I Convert My Bike To An Electric Bike?

You sure can!

Here’s a guide on how to fit just that!

Check out more tips & tricks

Final Thoughts

Using a kit to give your bike the increase in performance you’re after is a great result. It means you can carry on using your old bike time again.

Every kit should come with the correct amount of components so that you are about to fit the setup on your own (or with friends!). However, if you aren’t totally comfortable with the mechanisms and how all the machines operate then don’t be afraid to seek expert assistance.

What model interests you?

Amy L

About the author

I'm Amy, A writer and when I'm not writing, I'm usually found on two wheels! I own several bikes; my favourite has to be my faithful Bianchi Infinito CV. We've been through a lot together - we've even been to Paris together...twice!. My first carbon bike. My first love. Cycling is my passion and climbing is my thing, so if there's a climb out there you think I should know about - let me know!


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