Eso was a Czech motorcycle factory producing only racing machines from 1949 until 1964, when it joined Jawa. ESO was founded by a motorcycle racing driver Jaroslav Simandl, and made bikes in 250, 350, and 500 cc, primarily for speedway, moto-cross and ice racing.[1] Engines were sourced from J.A.P. during the first year, and then an engine of ESO's own after 1950, first copied from J.A.P. and later of their own design.[2] The factory produced a prototype microcar in 1959, The ESO-T-250. It had a fibreglass 2-seater body with many components from Jawa-CZ.[3]