EMC - Supercharged
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EMC D2-492-38-11
Photo ou archives : F-M. Dumas

Capacity : 350
Model : Supercharged
Production : 1948 -
Category : (R) Racing


350cc Supercharged - 1948

A lost cause

In 1947, Dr. Joseph Ehrlich, an unrivaled two-stroke expert, designed this highly sophisticated 350 with a double piston, two carburetors and a supercharger.

Not Really a Supercharger

Even though supercharged engines were barred from racing after WWII, the ingenious doctor attempted to qualify his 350 by arguing that it was not really supercharged. Whereas on four-stroke engines superchargers were fitted between the carburetor and intake valve, he argued, on this two-stroke engine, he had merely fitted an internal device that – as on pre-war DKWs – compressed the mixture in the crankcase. The EMC was not allowed to race in the 1948 TT. Its extremely short career was limited to a few races as a prototype with no rear suspension in 1947, of which the Hutchinson 100 was the highlight.

Three Pistons but Only One Spark Plug

This unique EMC had three cylinders but only one combustion chamber. The engine was effectively designed on the principle of a U-shaped double piston with a common combustion chamber (as on the Puch) with a third piston that had a short stroke (130x40mm) at the front of the engine that compressed the mixture admitted into the crankcase by the two big Amal TT carburetors. This compressed mixture was forced through three transfer ports into the rear cylinder, ignited and expelled through ports in the forward cylinder. These subterfuges allowed EMC to claim 45 hp, against the 30 hp developed by the then unbeatable AJS 7R.


Engine: 315cc (50x80mm) water-cooled "twingle" with common combustion chamber

Power Rating: 45 hp @ 5500 rpm

Valves: two-stroke with pumping-cylinder supercharger

Fuel System: two 29mm Amal TT carburetors

Transmission: Burman Racing 4-speecl, chain final drive

Suspension: Dowty oleopneumatic forks (front); swing arm with twin spring/dampers (rear)

Brakes: 7 inch tapered drum (front & rear)

Wheels: 3.00x20 inch (front); 3.25x20 inch (rear)

Restored from near-derelict condition 43 years after it first raced, the sole EMC is now a prized exhibit in the Sammy Miller Museum.

Motorcycle encyclopedia Moto Passion, realised by François-Marie Dumas, include almost 2000 photos presented with an exhaustive history of the motorcycles exhibited.

This unique collection has been realised with the participation of many specialists. With many thanks in particular to Yves Campion, Michael Dregni, Didier Ganneau, Jean Goyard, Helmut Krackowizer, Michel Montange, Christian Rey, Bernard Salvat, Mick Woollett, etc

One can order here

  • Original cards on paper (in french)
  • High resolution scans or original documents presented and signed with my name.

Please contact me at info@moto-collection.org for conditions and copyright.

© Tous droits réservés
François-Marie Dumas

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