Sunbeam 1918 4hp Military Model France 545cc 1 cyl sv 3511

Sunbeam   1918  4hp  French Military  Model  545cc side valve single  frame # 7444 engine # 134 7291 gearbox # 8777

A Sunbeam with a difference!  Over the years we have handled over 80 Sunbeam motorcycles, but this is the first  to enter our premises that is fitted with belt drive. She’s a pretty rare bird, the Marston Sunbeam Register knows of only six survivors, including this one.

When WWI broke out, some civilian 3½hp Sunbeams were used by the British Army but the biggest user  of military machines on the Western Front was the Royal Naval Air Service (forerunner of the Fleet Air Arm), which ordered the 3½hp as its favoured model. The Imperial Russian Army ordered 1,450 Sunbeams, among other makes, most being delivered via Archangel until the Revolution prompted an embargo, after which they were redirected to other armies. France took up to 1,000  solos and  a number of V-twin combinations that were used for ambulance work.  Italy ordered 500 3½hp models. The solo machines the French ordered were not the standard 3 ½ hp 499cc chain-driven machines, but to bring the Sunbeams into line with other French machines it was specified they should be belt-driven.  To provide some extra power a larger 545cc engine was fitted, with longstroke dimensions of 85 x 96 mm. This engine had been designed in 1915 by John Greenwood and had been used in experimental  competition machines, but not in standard  road machines. Production of the 4hp army machine started in 1916 and by the end of 1918 some thousand had been delivered.

The Marston Sunbeam Club and Register have acknowledged that frame, engine and gearbox numbers are in line with the information they have on surviving examples.  Not much is known about this machine’s history, she has been restored in the past and was for some years part of a static collection. The engine is running but some recommissioning may be at hand.  This very rare Sunbeam comes with acetylene lighting system, Amac carb, Bosch magneto and foot-operated claxon horn.