There are several problems with small motorcycle (moped, scooter) engines of 50cc-125cc displacement, and even up to 200cc for special applications. Lack of engine power and design complexity of a multi-valve cylinder head are the most important problems.Despite some isolated attempts and several patented works the small engines of 50cc to 350cc displacement undeservedly remain without adequate air charging means - neither superchargers nor turbochargers are offered to the market.This article presents a theoretical basis on how to improve high performance characteristics of a motorbike by supplying a working cylinder with additional compressed air under certain conditions. A few versions of a positive displacement air compressor (supercharger) have been developed, built, and used for engine boosting. Road tests of the pitbike motorcycle equipped with our small rotor-vane compressor were performed. The results exceed expectations of the supercharger's performance and efficiency. Thus, to reach 50km/h for the motorcycle powered by the 50cc four-stroke engine equipped with the supercharger, 40% less time is needed than for the same motorcycle powered by a naturally aspirated engine.