A Brief History of the Marque
Built in Modena by Vittorio Guerzoni, his first machine was a motorised bicycle with a four-stroke engine of 106cc (50x54 mm) with automatic inlet valve. It had a Bosch and a unit-construction 2-speed gearbox. The chassis is fitted with Aurora forks which Guerzoni manufactured and sold to other companies. The following year a Sport version capable of 70km/h was offered, and in 1923 a more powerful 123cc machine joined the range, now with a tappet-controlled inlet valve and a separate 2-speed gearbox.
In 1925 he presented a motorcycle with a 248cc SV parallel twin engine which was created using two cylinders from a 125 on a common crankcase of unit construction with a 360 ° crankshaft, forced lubrication and a three-speed gearbox, housed in a cradle frame. The touring version had an aluminium crankcase and could achieve 80 km/h at 4000 rpm and the Mignon SS was good for 129 km/h at 5500 rpm.
In 1928 they announced a new 250cc single which did not enter production, but later that year they displayed a 250cc twin. 1929 saw the introduction of 125cc Turismo and Sport models (SV and OHV) and the 250cc twin, all with 3 speed gearboxes.
A 175cc OHV motoleggera was became a popular choice, suitable for daily commute and sports work.
The two-stroke engines were abandoned in favor of four-strokes, with the chassis and bodywork remaining the same.
1932 saw success on the racetrack using an inclined chain-driven DOHC four-speed engine with foot change. Their was an association with Enzo Ferrari's Modena factory during the development of these machines - according to The Vintagent, a Norton OHC engine was dismantled and some of their ideas were incorporated into the Guerzoni engine. However, it did not prove powerful enough for Enzo's taste, and the project came to an end.
In January 1933 an article in Motociclismo spoke of a new 500cc sports machine derived from the previous years racers. It had an inclined DOHC and was ridden by Guglielmo Sandri who won races at Chieti and Asti that year. Manicardi writes that it looked more like a Moto Guerzoni than a Mignon.