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Guide to Buying Bicycle Motor Kits


Congratulations on choosing Live Fast Motors!

We are committed to helping the novice hobbyist, seasoned old-timers, and professional outfits enjoy the best possible bicycle motorizing experience.

If this is your first bicycle motorizing project, we are excited to help answer your questions and provide you with tips, so you can have a successful build and enjoy your new, motorized bike. If you're an old hat at this, we've got tips, tricks, and suggestions that can help you create another motorized masterpiece.

Please read the following to help you decide which Live Fast Motor Kit is right for you!

Picking the right motor size for you:

The right motor size varies based on your individual needs and preferences, including rider weight, terrain, top speed, and torque.

Rider Weight:

Riders who weigh less than 200lbs should pick the smallest motor size that meets your needs, as smaller motors have less vibration and are easier on the rider and bike. For average weight center mount riders, 48/50cc motors generally do the trick.

Riders who weigh 200lbs or more are better off going with a 60cc or bigger motor size. A smaller motor may still carry heavier riders on flat terrain, but you can expect lower top speeds.


Flat terrain requires less torque, so smaller motors perform just fine – again depending on rider weight, etc.

If you live in hilly country with moderate to big hills, you should consider a bigger motor. Coasting down hills can be an exciting thrill, while climbing is made much easier, if you have a bigger motor. On steep hills, you might need to pedal a bit, as well. The bigger the hills, the bigger the motor.

Top Speed:

There is little difference between the top speed from the different motors for normal weight riders. As mentioned above, speed does become an issue with heavier riders. Heavier riders would benefit by picking a bigger motor. Generally, we recommend going with the smallest motor that's right for you.


Bigger motors offer more torque, which is useful for hills or heavier riders. If you are a smaller rider on terrain that is generally flat, there is not much need for the extra torque.


Picking sprocket size:

Higher tooth sprockets give you higher torque and lower top speeds, while fewer teeth will give you less torque and higher top speeds.

  • 48-tooth sprocket – Highest torque, lowest top speed
  • 44-tooth sprocket – Great balance between torque and speed; Recommended for all around use
  • 40-tooth sprocket – Higher speeds, lower torque
  • 36-tooth sprocket – Reaches ultra-high top speeds and a faster finish, least torque and slower starts


Choosing Between Center Mount, Rear Mount Chain Drive, & Rear Mount Tire Roller:

There are a few factors to consider when choosing a motor kit for your bike, ranging from where you intend to ride, how loud your motor is for your neighborhood or area, how challenging it is to install, etc. Get the scoop on the popular options here:

Center Mount Motor Kits:

Center mounts are great for hobbyists to tool around and ride around the neighborhood. The OCC Chopper Build-Out Package can turn your Schwinn Stingray into a mean, motorized Chopper. Other accessories and upgrade kits can make this a great project with a satisfying, beautiful result. The ride is fun and worth the work. Serious hobbyists tend to build with center mount motors. Some mechanical skill and elbow grease is needed. Time to install will vary based on level of mechanical experience. A novice shouldn't be afraid to tackle this project, but they also shouldn't expect to slap it together in a few minutes, either. It takes time and tinkering for each customized installation. Since center mount motor kits require mounting space, larger “men's” bikes with an open triangle in the center frame are required.

Rear Mount Chain Drive:

Rear mount chain drive motor kits are the best option for those seeking more serious transportation. Like center mounts, the chain drive kits require basic mechanical skill, elbow grease, and patience to complete the build out. They can attach to a wider range of bicycles, including both men's and women's frames. Although still somewhat noisy (all of the engines make noise), the chain drive is quieter than the other rear mount option – the tire roller. Rear drives can tip some without flooding the bicycle engine.

Rear Mount Tire Roller:

Rear mount tire roller motor kits are the easiest kits to install. Although they require less time and mechanical skill, they don't just install themselves. You will need to follow basic instructions and use basic bike tools to install. The tire rollers offer the smoothest but loudest ride of any motor type. If you live in a neighborhood that restricts motor noise, you might consider a different kit. The 40cc tire roller is very loud, while the 40cc chain drive is more acceptable in terms of motor noise. Rear drives can tip some without flooding the bicycle engine.

Choosing a Bike for Your Project:

Choose a style and look that you like. Try getting on and off the bike. Make sure that you feel comfortable handling the bike before beginning your project. If you require a low frame to get your leg over the bike, choose a girls bike or other low frame with a rear drive motor kit. Rear drive motors can tip some without flooding the bicycle engine, so you can lower the bike when getting on and off.

For the center mount motors 48,60 and 70CC: The Sun, Schwinn and Huffy Beach Cruisers all seem to work well. Many Mountain bikes will work also. It should be a mens' bike so you will have a place to mount the gas tank. The most important element is to have enough room in the "V" area of the bike. A good way to determine this is to take two sticks 11 inches long each. Form an "X" with the two sticks. If the X fits in the V area of the bike you will have enough room for the motor. The rear mount TR2 friction roller, and the CD4 rear mount Chain drive will fit most bikes.

Choosing Between 2-Stroke and 4-Stroke Options:

2-Stroke engines offer more torque. They use a Gas/Oil Mixture. You don't have to check the oil separately. They tend to make more noise and emit more exhaust.

4-Stroke engines offer a quieter, smoother ride. They emit less exhaust. They take only gas in the gas tank. You must check and maintain oil levels separately.

Why is my chain breaking?

A broken chain can put an end to the day's fun, so avoiding common chain issues can help you ride without worry. One of the most common issues that leads to broken chains is that the sprocket is not properly centered and wobbly. If you see the chain going up and down, it is likely that your chain is not centered. Our custom clam-shell sprocket adapter has been designed to help resolve this issue. The large clam shell comes with spacers to avoid contact with the brake arms.

Why does my chain pop and snap when I let off on the gas?

When you let off the gas, the slack in the chain as the motor stops pulling the chain through the motor can pop and snap. It also adds vibrations while riding. The rider's hands can become numb from the excessive vibrations caused by chain fluctuations. Live Fast Motors has developed a custom spring loaded chain tensioner that helps eliminate extra vibrations by keeping proper chain tension throughout the ride, including when you let off the gas. Using this custom part can be the difference between enjoying your motorized moped or bide versus hoping to get off of it.

Installation Difficulty:

If you are not the most mechanically inclined person, the tire roller is your best best. However, if you are comfortable with basic mechanical tasks or are willing to learn, any of the kits can be used. All kits come disassembled and require basic troubleshooting and problem solving. Step-by-step instructions are available on this website. If you get stuck, you can call us for additional suggestions or tips. We want you to succeed, and we know that it can sometimes be a challenge to motorize a bike. Since every bike is different, there are no perfect methods. However, Live Fast Motors has developed a line of custom parts that have simplified many of the difficult assembly and operation problems. Those parts are available in certain upgrade kits and sold separately. Including clam shell sprocket adapters and spring-loaded chain tensioners, among others.

Tools Suggested to Complete the Project:

Depending on the project you choose, you will need access to basic shop tools like wrenches (alan wrench may be helpful), hammers, files, drills, etc. You can find more detailed information about required or recommended tools in the instructions. Some custom bike tools may be included in your shipment, depending on the kits or parts you order.

Building your own motorized bicycle is a satisfying and fun project for the hobbyists and the novice, alike. Soon, you'll be able to zip around on your new ride, getting mileage that can't be beat! Live Fast!