MOTOSACOCHE

350/500cc A50 - 1928

A great British rider -engineer

Dougal Marchant was one of the great British rider-engineers. He arrived at Motosacoche in 1927 via JAP, Blackburne and Chater-Lea, bearing the drawings of the M35, a superb overhead-camshaft 350, with which he broke records at Montlhéry. After six M35s had been built, Motosacoche passed this excellent design to Triumph, TWN and Standard.

Instant Success

The 350 and 500 "A" that Marchant created in 1928 were refined developments of the M35 and were instant successes. They could be recognized by the magneto mounted behind – rather than in front of – the cylinder. Wal Handley won both classes at the 1928 Grand Prix of Europe meeting in Geneva, while Richard came in first in the French 350cc GP.

What's in a Name?

The following year, Handley won the Italian GP with a new 250cc version and set several records with the A50 at Montlhéry, including 100 kilometers covered at 109 mph. For commercial reasons, these machines also raced bearing the emblems of Condor, OD, Standard, TWN, New-Map and Monet-Goyon. In the French GP, Monet-Goyon-badged Motosacoches won the 500cc category in 1928 (Gaussorgues) and the 350 (Gaussorgues) and 500 (Richard) classes in 1929. The 350cc event was won by Debaisieux in 1930. The unpredictable Marchant left Motosacoche in 1929 to join FN, though he returned after WWII. He was replaced at Motosacoche by Bert Le Vack, who finished up the A-series engine, then turned his attention to refining the Jubilee and D models designed in the interim by the Swiss engineer Nebel.

SPECIFICATIONS

Engine: 496cc (82x94mm) air-cooled single-cylinder four-stroke; dry-sump lubrication; magneto ignition

Valves: single overhead-camshaft driven by shaft-and-bevel gearing

Fuel System: carburetor

Transmission: gear primary drive, chain final drive

Suspension: girder forks (front); rigid (rear)

Brakes: drum (front & rear)

Wheels: wire (front & rear)

Maximum Speed: 96 mph

Marchant sealed his engines so that nobody could copy his methods. He is seen (inset, right) with Wal Handley's 1928 European GP-winning A50.