Moto Guzzi - Supercharged
 Back to brands list

Moto Guzzi D2-492-52-08
Photo ou archives : D. Ganneau

Capacity : 250
Model : Supercharged
Production : 1939 - 1952
Category : (R) Racing


250 Supercharged Single -1939

The first supercharged single

Prior to WWII, the fashion for superchargers on competition machines was strong. Guzzi could not be left off this technical bandwagon, and its racing 250 proved particularly suitable for a forced induction. In 1938, the 250 was fitted with a vane-type Cozette supercharger, driven by a train of pinions.

"Buffer Chamber"

To lessen the effects of pumping caused by the constant up-and-down motion of the piston in the single-cylinder engine, a "buffer chamber" was fitted between supercharger and cylinder head to absorb the variations in pressure due to the blower.

Racing and Record-Breaking

Initially destined for record-breaking, the supercharged 250 was also raced in GPs in 1931. Its unfaired speed was not much over 118 mph, but despite that, it enjoyed a fair amount of success. If Omobono Tenni and Stanley Woods were forced to retire when they were leading the TT, the Guzzi had its revenge in the German GP, when Guglielmo Sandri and Nello Pagani outdistanced the supercharged DKWs. The high point of the season was the flying kilometer record achieved by Raffaele Alberti in October, at an average of 132.48 mph. In 1940, Alberti won his class in the Milan-Taranto event with an experimental fuel-injected version known as "Gerolamo." In 1952, this engine was used by Gino Cavanna to establish a new kilometer record- with a sidecar- of 137.47 mph.


Engine: 247cc (68x68mm) air-cooled horizontal single-cylinder four-stroke; drysump lubrication; magneto ignition

Power Rating: 38 hp @ 7800 rpm

Valves: shaft-and-bevel-driven overheadcamshaft

Fuel System: carburetor

Transmission: 4-speed, chain final drive

Suspension: girder forks (front); swing arm (rear)

Brakes: drum (front & rear)

Wheels: 2.75x21 inch (front); 3.00x21 inch (rear)

Weight: 291 lb

Maximum Speed: 125 mph


Whether in its racing version or as a recordbreaker with extended wheelbase and rear wheel disc, the 250 Guzzi well demonstrates the technical excesses of the period prior to WWII.


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 for conditions and copyright.

© Tous droits réservés
François-Marie Dumas

Accueil - Motos NOUGIER - Motos insolites - Motos japonaises - Unusual Motorcycles - Scooters du Monde - Motos Passion - Motos GILLET - Liens - Contact

Moto Collection - François-Marie Dumas

Valid XHTML 1.0 Transitional CSS Valide !

Mentions légales