Sunbeam Motorcycle

The Marston Sunbeam Club & Register

The 350 Side Valves

349cc, 75 x 79, 2 3/4 HP, 1912-1914

John Marston Ltd had started making bicycles in 1887, and had carried out experiments in 1903/04 with power-assisted bicycles, using Motosacoche engines. It was not until Harry Stevens (of AJS fame) was contracted to design an engine for JML that development started in earnest. John Greenwood was recruited from Rover to design a complete motorcycle, and the result was the 75 x 79mm 2¾ HP machine illustrated below. Greenwood made a few changes to Stevens’ engine, most noticeably moving the magneto from in front of the cylinder to behind it. The machine also featured a two-speed countershaft gearbox and all-chain drive, fully protected by chaincases.

350 SV

The 1912 production version, unlike the illustration in the 1912 catalogue, was fitted with much smaller and less bulbous primary and final drive chaincases, as is clearly shown in the advertisement from October 1912. Although listed as having a green-painted tank in the 1912 catalogue, the 1913 catalogue shows the tank finished in the familiar black with gold leaf lining. It was, from the start, entitled “The Gentleman’s Motorcycle” in the catalogues and advertising.

The 2 ¾ HP was successful in trials from the very beginning, with John Green wood winning a gold medal in the ACU Reliability Trial in October 1912, the best performance by a 2 ¾ HP machine. That the second Sunbeam didn’t also win a gold medal was due to the fact that the rider forgot to turn the petrol on after the lunch stop!

1914 was the last year of the 74 x 79mm machine. A 2¾HP model re-appeared in 1922, but it was a very different machine with a very different engine.

349cc SV

From the 1913 Catalogue

349cc SV

Club Logo

The Marston Sunbeam Club & Register

Copyright © 2015 · All Rights Reserved

The Marston Sunbeam Club & Register Ltd is a company limited by guarantee registered in England and Wales Registration No. 7230550 - Registered office: Lewis Onions Solicitors, Allium House, 36 Water Street, Birmingham B3 1HP


Face Book