The second requirement is also radically affect the dynamic qualities that are in direct proportion to the ratio of weight to power. The lower the overall weight of the motorcycle, much of which falls on the engine, the higher ceteris paribus his speed and better acceleration.

Engine weight has been the subject of special attention, when the technical regulations restricting the weight of motorcycle racing. In this case, any savings resulting weight of the engine could be facing an increase in its working volume and. therefore, gave the gain in power. Reliability is essential to avoid forced stops, and the more mechanical failures during the race.

The intervals between the first three bikes at the finish of the race often are only a few seconds and often measured in fractions of a second even. Therefore, shut down by the most insignificant cause, might deprive a race bike almost won the victory. Other requirements relating to durability, cost, efficiency, ease of repair and maintenance, recede into the background. They can be sacrificed, if it facilitates the development of basic skills.

Sometimes, however, and fuel consumption must be taken into account: a machine capable of passing the full distance with a minimum number of stops to take stock of fuel, shows a higher average speed. Engine power is determined by the amount of heat energy transferred to mechanical work and, consequently, the overall fuel consumption per unit of time.