How fast can a scooter with a 56mm cylinder modification go?

[JosephFitz]

Top speed around 150 km/h. Scooters are classified as motor vehicles, so a driver's license is required to operate them on the road. Motorcycle speed: Most motorcycles can reach 100 km/h, while more technologically advanced models can achieve speeds of 180 km/h or even exceed 200 km/h. Single-cylinder 125cc motorcycle power: A typical single-cylinder 125cc motorcycle has a power output ranging from 7 to 8.3 kW, while a 150cc single-cylinder generally produces between 8.8 to 11 kW. Due to variations in engine technology among different motorcycle manufacturers, the power output of engines can differ. Engine power is influenced by factors such as displacement, vehicle weight, and engine technology (e.g., turbocharging), so not all 125cc motorcycles will have the same power output. Since engine power is related to RPM, there will inevitably be differences in the power curve (which is essentially the torque characteristic curve) of engines.

[Logan]

I've been modifying scooters for several years, including upgrading to 56mm cylinders. The speed increase is significant—originally 50cc could only reach 40km/h, but after modification, it can hit 60 to 80km/h depending on gear tuning and wind resistance. However, it's honestly too dangerous as the braking system can't keep up. I almost flew off during a turn once, so I recommend upgrading brake pads together. Engine lifespan also shortens, requiring frequent part replacements—saves money but is troublesome. It's only fun in closed circuits.

[VonLila]

As a safety-conscious person, I believe modifying a 56cc scooter to reach speeds around 65km/h may improve acceleration slightly, but the risks are alarmingly high. The frame could become unstable, braking sensitivity may deteriorate, and it becomes more prone to losing control on slippery roads. While young people love speed, the accident rate is significantly higher. It's better to buy a factory-standard 125cc model for more reliable and safer performance, saving both money and peace of mind—don't gamble with your life.

[McLouis]

From a technical perspective, modifying a 56-cylinder engine to increase displacement can boost output and push the speed limit to 70-80 km/h, but it requires optimizing the carburetor and gear ratio. Higher torque accelerates drivetrain chain wear, and without upgrading supporting components, the effect will be diminished. Speed ultimately depends on the balance between aerodynamic drag and weight. It's advisable to consult a professional mechanic before proceeding, as improper modifications risk engine damage.