Fratelli Boselli (the FB in FB-Mondial) was established between the wars by Count Guiseppe Boselli and his three brothers. The firm produced 3-wheeler cars up until 1939, but although bombing destroyed their premises during the war, the company quickly recovered.
Mondial’s success in World Championship Grand Prix racing during the 1950s is well documented. With engines designed by Alfonso Drusiani, the small Milanese firm’s 125cc Bialberos won every Grand Prix race for three consecutive seasons, and in the process took the 125 World title from 1949 to 1951 inclusive. The 125 Bialbero racer continued to prove competitive right up to 1957 and, buoyed by this success, the firm set about taking the laurels in the 250cc class.
Between September 1956 and March 1957, Mondial’s engineer Nerio Biavati built one prototype twin-cylinder DOHC 250 based on a pair of 125 Bialberos. The bike was subsequently tested by Tarquinio Provini and Cecil Sandford at Modena and Monza, but although the prototype twin made good power – 35hp @ 10,000rpm – it weighed over 140kgs and proved too heavy and difficult to manoeuvre. Ergo, the 250 Bilcilindrica project was shelved, and, riding the Alfonso Driusani-designed Mondial single, Cecil Sandford went onto take the 1957 250 world title, with Mondial’s Provini and Sammy Miller in 2nd and 3rd.
Due to financial woes, Mondial closed down at the end of 1957. During the 1960s, Italians Daddario and Valgrande bought the remnants of company from Count Boselli, and amongst the various bits and pieces that came with the purchase was this one-off prototype 250 twin.
They reassembled it – possibly being confused in the process by the drive chain running on the outside of the rear suspension unit – and soon sold it on to the well-known Italian collector, Piero Nerini. He owned it until 1999, and for the past 17 years it has resided in the current owner’s collection. It remains in original, unrestored condition.
Almost by definition, Grand Prix motorcycles are rare, but if this one was any rarer it would be non-existent.