J.E. Smith 1920

BSA bicycle fitted with 1920 J.E. Smith (JES) 142cc Auxiliary.

The JES was one of the most popular of the auxiliary engines produced in the 1910s, as it had a good reputation for reliability. This example above is in good running order. JES were motorcycles produced from 1909 to 1924. The name came from the initials of J. E. Smith of J. E. S. Motor Works of Gloucester.

More information about BSA; see BSA Streamlight

J.E. SMITH MOTOR WORKS. Gloucester, England

1909. JES was first offered as an auxiliary motor set to fit within a bicycle frame and drive the rear wheel by belt. The engine was a 1hp, 116cc four-stroke with a front-mounted gear-driven Fischer magneto, and the whole machine was a bicycle with braced forks and a fuel tank hung from the top tube.

The JES continued in this form for many years and was also built and listed as the City and the Imp.

1920. The engine was enlarged to 142cc and inclined in the frame, but the original simple concept remained.

1921. Added to the list was a 170cc two-stroke miniature motorcycle with two speeds and a vertical engine.

1922. A single-speed version appeared.

1923. The four-stroke was dropped, but the single-speed two-stroke ran on with a three-speed version. To these were soon added a lightweight with four-speed chain-transmission and the choice of 247cc two-stroke or 249cc ohv Blackburne engines – a move to more conventional machines.

1924. The company acquired the Connaught marque of Birmingham, and for that year there were just two lightweight models. One with the 247cc two-stroke, but the other with a 348cc sv engine. Both had three-speed Burman gearboxes and chain-cum-belt drive. The auxiliary motor set was re-introduced. This was a 123cc two-stroke engine, chain drive and in either gents’ or ladies’ style of bicycles frame. It was also available as a conversion kit. The make did not survive beyond the end of that year. The specification sheet reproduced here is for the 1909 JES, which was 116cc.