The engine displacement of a motorcycle is commonly measured in cubic centimeters (cc) and is often used as a rough indicator of the motorcycle's power and performance. However, it's important to note that engine size alone doesn't determine a motorcycle's speed or performance.
Fast motorcycles can vary in engine displacement, and there is no specific cutoff for what constitutes a "fast" motorcycle in terms of cc. Generally, sport bikes or superbikes are known for their high performance and speed, and they often have larger engine displacements compared to other types of motorcycles.
Sport bikes typically range from around 600cc to 1000cc and above, with some models even exceeding 1300cc. These motorcycles are designed for high-speed performance and often feature advanced technologies, lightweight construction, and aerodynamic designs.
It's worth mentioning that other factors such as aerodynamics, weight, power output, torque, and rider skill also play significant roles in determining a motorcycle's speed and performance.