Calthorpe 350 1926
While official AJS, Sunbeam, and Norton motorcycles dominated
350-and 500-class racing, private European racers made do with whatever they
could find, including old side-valve Sunbeams that were still in fine condition
and still able to give high performance; modified production models of the
Norton; and rod-and-rocker Calthorpes.
These were the only genuine racing motorcycles for those
private racers who could not afford the latest models of the British
Calthorpe was a small company in Birmingham, England. It had started out by
manufacturing accessories and mounting other people's engines on its own
chassis. Subsequently Calthorpe built its own engines as well. Because of the
careful handwork that went into the design, these engines performed well and
were highly reliable.
In 1926 Calthorpe went into racing, Chassis: Single
cradle, tubular, open below. Front, elastic suspension; rear, rigid
Brakes: Front and rear, side drum
albeit not directly. The company sold racing models to private racers at
reasonable cost. In any case, the Calthorpe 350 soon became popular thanks to
its construction technique. The single-cylinder engine with head valves was
controlled by rod and rocker in a cylindrical casing outside the finning. The
chassis was open below and the fuel tank served a dual purpose, holding
lubricating oil as well as fuel.
Motorcycle: Calthorpe 350 Manufacturer: Calthorpe Motorcycles
Birmingham Type: Racing Year: 1926
Engine: Calthorpe single-cylinder, vertical, four-stroke, overhead valve
distribution, rod and rocker. Displacement 350 cc.
Transmission: Three-speed separate
Maximum speed: About 80 m.p.h.