The Gobbetto (Little Hunchback) was presented at the 1951 Salone del Ciclo e del Motociclo in Milan. These factory racers won the 1954 Italian Championship held at Autodromo Nazionale di Monza and are otherwise notable for the large number of decibels emitted from its very brief exhausts.
Series One 1951-1952 (two versions), series two 1953-1955.
The series one was initially fitted with a flywheel magneto and cast iron cylinders, with the second version of the series one was released in 1952 had alloy barrels and a chain-driven magneto. The series two machines retained the engine and external magneto of the later series one and were graced with a redesigned frame and fuel tank.
Production figures: around 50 (PA says 40, another 50, a third 60)
The Gobbetto road racers are the most collectible of all Rumis.
Sources: Phil Aynseley, et al.