10 Best Bicycle Engine Kits 2025 in the United States

This 100cc 4-stroke gasoline bicycle engine kit offers solid power with 3.5 horsepower, allowing speeds up to around 50 km/h, which makes it a good choice for riders wanting a noticeable boost without going full motorcycle. Its air-cooled OHV (overhead valve) engine design helps reduce fuel consumption and carbon buildup, making it more economical and reliable over time. The kit includes a large 0.52-gallon fuel tank, so you won't need to refuel frequently during rides. Durability is a strong point here, thanks to corrosion-resistant materials like aluminum and steel, plus a robust chain and belt system designed to handle up to 440 pounds, suitable for heavier frames.

Noise levels are moderate, about 75dB, so it won’t be completely silent but should be acceptable for outdoor use. Installation might require some mechanical skill since it’s intended for large triangular bicycle frames or motorized bike modifications, and compatibility depends on your bike’s frame size and setup. This makes it a great budget-friendly option for those wanting to convert a bicycle into a motorized bike without investing in a full motorcycle.

It may not be the best fit if you need a simpler plug-and-play system or if your bike frame is smaller or uniquely shaped. Also, while maintenance is relatively straightforward due to the 4-stroke engine design, some familiarity with engine upkeep will be helpful to keep it running smoothly.

The YUNLAIGOTOP 100cc Bicycle Motor Kit is a powerful 4-stroke gasoline engine system designed to transform a regular bike into a motorized one. With a 100cc displacement and a maximum speed of 3600rpm, this kit offers robust performance suitable for commuting and short trips. The 4-stroke engine is quieter and more reliable than its 2-stroke counterparts, thanks to its stable and continuous power output and lower operating temperatures. It also features a forced air cooling system and a recoil start mechanism, making it user-friendly and efficient.

The engine kit is constructed with a high-performance aluminum alloy body, ensuring durability and longevity, while the plastic casing protects the engine from potential damage. This kit comes with a double belt drive, enhancing its reliability and reducing maintenance needs. However, users should be aware that the installation process might be moderately complex and may require some mechanical knowledge or professional assistance. The kit's compatibility with various bike models is an advantage, but it’s essential to check your bike’s specifications before purchasing.

With a customer rating of 4.2 out of 5 stars, this engine kit is well-regarded for its quality and performance. While it is on the pricier side, the included one-year warranty for manufacturer defects adds value. The YUNLAIGOTOP 100cc Bicycle Motor Kit is an excellent choice for those seeking to motorize their bicycle with a durable and high-performing engine.

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.