Web Analytics

 Benelli - 500 Gran Premio Bialbero
 Back to brands list

Benelli Gran Premio Bialbero motocyclette motorrad motorcycle vintage classic classique scooter roller moto scooter
Photo ou archives : F-M. Dumas

Capacity : 500
Model : Gran Premio Bialbero
Production : 1938 -
Category : (R) Racing


500 Grand Prix – 1938

Unfulfilled promise

Benelli made its racing debut in 1923, with a standard 125 bored out to 150cc and specially reworked for Tonino, one of the six Benelli brothers, to race in the 175cc category.

Major Step Forward

Benelli took a major step forward in 1927 by building an overhead-cam 175cc four-stroke designed by Giovanni Benelli, on which Tonino dominated his category in Italy that year. Tonino and his 175 Benelli again won the Championship of Italy in 1928, 1930 and 1931. The racing team contested international races in which the 175 won the Swiss GP in 1931, then the Dutch TT and the French and Belgian GP. Late in 1934, the Benelli brothers, encouraged by these successes, began the construction of new 250 and 500 singles.

Much Hope, Little Success

In 1935, the factory announced (with a certain degree of optimism) that the 85x87mm 494cc single would develop 50 hp and reach 109 mph. But its rider, Guglielme Sandri, was unable to prevail against the V- twin Guzzi. The 500 underwent a far-reaching program of modification for the 1938 season. Unlike Norton, which had just reduced the stroke of its Manx, the most expensive racing 500 of the period, Benelli adopted a longer, 101mm, stroke. The 1938 model 500 also had a complex swing arm rear suspension using coil springs encased in vertical tubes. Unlike the phenomenal 250, the twin-cam Benelli 500 enjoyed only local success; unable to beat the all-powerful Gilera Four, it was dropped in 1939.


Engine: 488cc (78.5x101mm) air-cooled single-cylinder four-stroke; aluminum head and cylinder; dry-sump lubrication

Power Rating: 46 hp @ 6500 rpm

Valves: twin overhead-camshafts driven by gear chain

Fuel System: carburettor

Transmission: 4-speed, chain final drive

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

Brakes: 9.8 inch drum (front); drum (rear)

Wheels: 21 inch wire (front & rear)

Weight: 309 lb

Maximum Speed: 121 mph

With an external oil pump, the engine of the Benelli 500 GP was festooned with pipes carrying oil from the sump to the oil radiator and then to a separate oil tank.

Le fichier Moto Passion réalisé par François-Marie Dumas réunit près de deux mille photos accompagnées d'un historique très complet des machines présentées.
Il sera progressivement mis à jour ici et toute information complémentaire est la bienvenue sur info@moto-collection.org.

Cette documentation unique, qui constitue sans doute l'encyclopédie la plus exhaustive jamais écrite sur l'histoire de la moto, a été réalisée avec l'assistance de nombreux spécialistes dont principalement Didier Ganneau, Christophe Gaime, Mick Woollett, Jean Goyard, Bernard Salvat, Christian Rey, Yves Campion, Helmut Krackowizer, Michael Dregni, Michel Montange, etc. que je remercie ici.

Disponible sur demande :
- Les fiches originales sur papier
- Les photos et archives signées de mon nom en haute définition ou les documents originaux.
Me contacter sur info@moto-collection.org pour les conditions et droits d'utilisation.