The kit is designed to work with a wide range of bicycle frames, as every frame is different, but neither the engine nor the exhaust pipe would actually fit within my bike frame, so I had to modify both. There was a lot of fine tuning involved with the intake and balancing the fuel ratio in the carburetor, and I ended up replacing the kit’s carburetor with a model with better reviews online. The engine actually sounds, after the replacement, as one would expect it to, as a hum where each cycle burns the fuel efficiently. Before the replacement and the ratio-balancing, it seemed to sputter and had trouble accelerating. I don’t use the bike often, especially because it has become so difficult to get it working again every summer, but it was a fun building project and it taught me a lot about the components and mechanisms of real-world engines.