Moto Guzzi 250 Racers

Moto Guzzi 250 Single-shaft 1930

After the success of the 500 four-valve, Moto Guzzi turned in 1925 to the construction of a Vt-liter two-wheeler with the same general features as the 500, one that could also match the 500's racing achievements.
Thus was born the single-cylinder single-shaft 250. Because of the smaller cylinder diameter, only two valves were installed.
The model that appeared in 1926 had 15 h.p., which was not exceptional for the time. But, unlike other motorcycles, this one could generate that much power in all kinds of operating conditions.

A few months after it first appeared in racing, the Guzzi 250 set several world records. Guzzi tried for world records with motorcycles that had no special features but were adapted for Grand Prix racing. By 1935 the Guzzi 250 had won countless races and was a kind of mobile testing ground for the company's racing department. In 1927, fifty out of the sixty-two races won by Guzzi were won by the 250 model. In 1930 the 250 won thirty-six of the forty-nine victories the company had. Meanwhile the two-wheeler had undergone changes. The chassis had been modified.

The transmission acquired another gear and was given pedal control.
Moto Guzzi 250 Single-shaft, 1928-1929 model In 1935 Moto Guzzi gave a 250 and a 500 two-cylinder to the British racer Stanley Woods to drive at the difficult Tourist Trophy. For that occasion the 250 was given a new rear suspension. It was a very complicated elastic suspension system and also very heavy. Nevertheless Woods outdistanced all the other motorcycles in the class. To win the Tourist Trophy in those days meant admission to the elite of world racing. That year Moto Guzzi won in the 250 class and the 500 class at the Tourist Trophy, a truly memorable achievement.

Another feature of the 250 provided increased power. A fuel mixture °f gas, alcohol, and benzol raised the motorcycle's power to 23 h.p. at 7,500 r.p.m. This vehicle could often offer better performance than the finest racing 350s.

In 1937 the Guzzi people installed a Cozette supercharger, which increased power to 38 h.p.
The Guzzi 250 with supercharger set a host of new world records. In 1939 it did the flying kilometer at an average speed of 213 km./hr. (about 132 m.p.h.), a record that the best 500s of the time barely managed to equal.

Motorcycle: Moto Guzzi 250 Single-shaft Manufacturer: Moto Guzzi, Mandello del
Lario Type: Racing Year: 1930
Engine: Guzzi single-cylinder, horizontal, four-stroke, with overhead single-shaft distribution and bevel gear shaft. Displacement 246.9 cc. (68 mm. x 68 mm.)
Cooling: Air
Transmission: Three-speed, hand controls Power: 20 h.p. at 6,800 r.p.m. Maximum speed: About 87.5 m.p.h. Chassis: Continuous tubular double
cradle, rigid rear. Front, parallelogram
suspension Brakes: Front and rear, central drum

Moto Guzzi 250 Compressor 1938

Motorcycle manufacturers as diverse as Douglas, Garelli and Victoria had produced supercharged motorcycles during the 1920s, but the first blown Moto Guzzi was the Compressore of 1930. However, like many of the other supercharging projects of the era, it didn’t progress beyond the prototype stage.

During the 1930s Excelsior, Rudge and Velocette also experimented with forced induction, but it was BMW in particular that achieved considerable competition success with its various supercharged racers. By the latter half of the decade it was clear that to compete at the highest level it was necessary to use supercharged engines, and so in 1937 Moto Guzzi created a single-cylinder 250 with a French Cozette compressor.

The Guzzi 250 Compressore debuted in 1938 and the great Nello Pagani rode the bike to eleven victories at Monza, along with seven further race wins that year at other circuits, and 16 more the following year.

The 250 Compressore’s engine was essentially the same as the normally aspirated 250 Monoalbero’s but with a lowered compression ratio. It produced 48hp at 7,500rpm, while top speed was around 112mph (180km/h), or over 137mph (220km/h) in post-war record-breaking specification with raised compression (8.5:1) and sometimes running on alcohol. After over 20 years of service Moto Guzzi ceased production of the 250 Compressore in 1959.