Although there is no direct conversion between CC, or cubic centimetres, and MPH, miles per hour, there us a relationship between these two units of measurement. In motorcycles, engine displacement is measured in cubic centimetres. This measurement indicates the amount of space that pistons travel through in the engine and can provide an indicator of engine power and, thus, speed.
Identify the displacement of the motorcycle. This will typically be expressed as a three or four-digit number followed by the letters "cc." Higher displacement indicates larger amounts of available power and, thus, higher speed.
Weigh the motorcycle or find out the total weight from a reference manual.
Divide the weight by the displacement to identify the ratio of weight to displacement. Displacement can be used as a rough analogue to power. The ratio of weight to power quantifies how much power is available to move each pound of the motorcycle and how quickly the bike will accelerate, as well as the top speed. A lower ratio indicates that the motorcycle will be faster than another.