10 Best Bicycle Engine Kits 2025 in the United States

This 100cc bicycle engine kit is a solid choice for anyone wanting to motorize their mountain, road, gravel, or beach bike. It features a 4-stroke gasoline engine with a 100cc displacement, providing a respectable 3.5 horsepower and a top speed around 50 km/h, which is enough power for casual commuting or leisurely rides. The air-cooled design and double belt drive add to reliable performance and smoother operation.

Durability is a strong point here, with an aluminum engine shell, iron fuel tank, and rust-resistant steel chain that can handle up to 440 pounds, making it sturdy for different bike types and terrains. Its 0.52-gallon fuel tank and efficient fuel consumption (about 0.66 gallons per 100 km) mean fewer stops for refueling and cost savings over time. The engine runs quietly at around 75 dB, so it won’t cause much noise disturbance.

This engine kit suits riders who want a durable, powerful, and fuel-efficient upgrade for their bike and are comfortable with a bit of DIY assembly or have access to help. It is less ideal for those seeking plug-and-play ease or guaranteed service support.

The CUBELLIN 100cc Bike Motor Kit is a solid choice for those looking to convert their bicycle into a motorized bike. Its 4-stroke engine provides robust power with 3.5HP and a max speed of 50km/h, making it suitable for various terrains including mountain and road biking. Its air-cooling system and overhead valve technology enhance fuel efficiency and longevity, consuming just 0.66 gallons per 100km.

The kit's durability is notable, with an aluminum engine shell and iron fuel tank, ensuring a high max bearing capacity of 440 pounds. The package includes all necessary components for conversion, which could be complex for beginners but manageable for those with some mechanical skill. It is designed to fit bikes with large triangular empty frames, adding versatility in compatibility.

The product does require assembly, and its skill level is marked as advanced, which might deter newcomers. Additionally, while the noise level is relatively low at 75dB, it is still audible and might not be suited for noise-sensitive areas. The engine's size and weight could also affect the bike's balance and handling. This kit is particularly beneficial for experienced cyclists or hobbyists looking to upgrade their bike's performance and efficiency.

The CUBELLIN Upgraded 100cc Bicycle Engine Kit is designed to transform a regular 26"-28" bicycle into a motorized bike with a 2-stroke 100cc engine. It’s powered by gasoline and offers a top speed of around 48 km/h, making it a practical choice for those wanting to add extra speed without buying a full motorcycle. One of its standout features is its fuel efficiency—running about 150 miles per gallon, which helps keep running costs low.

Installation requires some mechanical skill, but the kit includes all necessary parts and a manual to guide through the process. The engine mounts use 8mm bolts instead of the common 6mm, providing stronger and safer attachment to the bike frame. The engine body is made of aluminum and iron components treated to resist wear, promising decent durability if maintained properly. However, as a 2-stroke motor, it will need regular maintenance like oil mixing and carburetor tuning for best performance. The kit comes with an upgraded carburetor that has adjustable settings, allowing better control over fuel delivery and easier starting in cold weather—an advantage for varied climates. It supports a maximum load of about 200kg (440 lbs), suitable for most adult riders with some cargo. This kit is especially good for users with limited budgets or those who want motorized assistance only occasionally or for short trips.

On the downside, the rigid suspension and absence of included brakes mean your existing bike setup must handle those safety aspects. Also, it may not fit all bike frames perfectly, so checking compatibility beforehand is important. While the speed and power are good for casual use, it’s not designed for heavy-duty or long-distance riding. This engine kit provides a cost-effective, fuel-efficient way to motorize a suitable bike with moderate speed and solid build quality, making it best suited for hobbyists or practical users looking for an easy upgrade rather than a full motorcycle replacement.