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Moto Guzzi's catalogue racer

(by Ian Falloon, Mar 2022)

Moto Guzzi
              250 racer



Making singles fly was once a Guzzi specialty

By 1926 the success of Moto Guzzi's racing program was beginning to pay dividends. There were now 350 employees at Mandello producing around 3000 motorcycles a year.


With the classic Guzzi layout of a horizontal engine, tubular double-cradle frame and three-speed unit gearbox now well established, the 250 would also follow this pattern.


Carlo Guzzi’s intention was to compete in the Isle of Man TT, and on May 1, 1926, made the new 250 available to the magazine Motociclismo for testing. The lines closely followed that of the C4V but the engine now had square dimensions, 68 x 68mm bore and stroke, and a bevel-gear driven single overhead camshaft operating two valves. These had an included angle of 58º, a very narrow angle for that time, and this undoubtedly contributed to be very high specific power output of 60 horsepower per litre.


In 1926 this was an extraordinary figure for normally aspirated engines, and only matched by the Delage and Bugatti Grand Prix cars.


With an 8:1 compression ratio, the 15 horsepower was produced at 6000rpm. This increase in rpm was enabled through the use of roller big-end bearings instead of plain bushes, and these were soon adopted on the 500cc C4V. Weighing in at only 105kg, the TT250 was capable of around 118km/h (73.3mph).


In June a 250 and 500 were taken to Isle of Man for Pietro Ghersi to ride in the Lightweight and Senior TTs.


On the TT250, now with a Binks hand throttle and André steering damper, Ghersi astonished the partisan crowd by finishing second behind CW (Paddy) Johnston’s Cotton and setting the fastest lap at 63.12mph (101.6km/h).


Unfortunately Ghersi was disqualified for changing an unspecified spark plug (to a FERT instead of KLG) during the race but it had been an impressive racing debut in the most prestigious race in Europe. He retired during the Senior TT.


Although the Isle of Man had been a disappointing event, 1926 was a very successful year for Guzzi in competition, with 42 victories.


A month after the TT, in the Circuito del Lario, Ugo Prini rode to victory in the 250 Class, although Pietro Ghersi was defeated by the Sunbeam of Achille Varzi in the 500 class.


The most important event of the year in Italy though was the Nations Grand Prix held at Monza in September. Here again the 250 was triumphant, with Prini and Ghersi joint winners. The TT250 was then marketed as a catalogue racer.

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