Benelli 250/4 supercharged
Images by Phil Aynsley
One of the more impressive bikes I have photographed is to be found in the fantastic Morbidelli Museum, in Pesaro on Italy’s Adriatic coast. Fittingly the Benelli factory was located in the town and Mr Morbidelli’s personal collection includes quite a number – with the sole example of the supercharged 250/4 being at the pinnacle.
Designed by Giovanni Benelli in 1939, the bike was a look to the future with its four cylinder water-cooled, short-stroke DOHC supercharged engine. Revving to 10,000rpm it made 52.5hp and was good for a top speed of 235kph. This was over 30kph faster than the factory 500cc Norton and Velocette singles, let alone the 250cc competition!
Italy’s entry into the war in 1940 curtailed further development and the bike (along with the rest of the company’s race bikes) was disassembled and it’s parts hidden, away from the factory – the motor down a dry well and the chassis under a hay stack in a barn. These were wise precautions as the factory was put to use producing aero engines and Pesaro was heavily bombed during 1940-41.
However, in completely Italian fashion, after Italy officially exited the conflict in 1943 work resumed on the bike, despite the Allies and the Germans still fighting on Italian soil. Mr Morbidelli told me the story of how the bike was once being tested on a long straight road that ran alongside a railway line. A freight train driver, on hearing what sounded like an attacking fighter diving on him from behind, stopped the train and bolted into the fields!
With the FIM banning forced-induction when racing was resumed after the war development was abandoned with the bike never having been raced.