of thermal expansion that afflicted these applications. The five cylindrical gears with straight teeth of the distribution (one of the crankshaft, three idle, one of the camshaft) were inserted (cascade) in a thin aluminum folder placed on the right side of the engine, on the top of which was mounted the "castelletto" of the distribution with the camshaft and barbells annexed. The whole was fixed to the engine head not rigidly, but leaving the coupling with a degree of freedom. The solution consisted in inserting two screws with the stem partially threaded (columns) in two holes in the castle and screwed on the two of the four prisoners of the thermal head. The threaded part joined firmly to the head, while the part of the threaded screw created a free, but very precise coupling with the two holes in the castle. The screws were tightened so as not to "crush" the castle, but so that they could leave a play of a few tenths of a millimeter sufficient to the two "blocks" (folder-castle/ cylinder-head) to flow over each other in the phase of expansion by the effect of heat, without interfering and creating those deformations that would have made the system unreliable. This solution was patented in 1927 and began the commercial and sporting success of Benelli, which lasted until the outbreak of World War II. (Patent No. 255634 of 29 Oct. 1927 "Arrangement for forming and fixing the transmission box for controlling the distribution shaft at the head in combustion engines") Two years after that, using a version specially designed for competitions, Tonino "the terrible" took to the track. He displayed an extraordinary natural talent as a rider and embarked on a very successful career which confirmed the company's exceptional capacity for development and production. Riding a Benelli 175, Tonino Benelli won four Italian championship titles in five years: in 1927, 1928 and 1930 with engine single overhead camshaft (SOHC) version, and in 1931 with the double overhead camshaft (DOHC) version. Unfortunately, a bad crash in the GP of the Tigullio in 1932 put an end to his short and brilliant career; on 27 September 1937 Tonino died following a road accident. As World War II loomed, the Benelli company debuted with a motorcycles with engine four-cylinder in line supercharged 250cc designed for racing with double overhead camshaft, liquid cooled and with a vane compressor, credited with a maximum