The MV Agusta 250 Monocilindrica Bialbero was a 250 cc factory racer manufactured by the Italian brand MV Agusta from 1956 to 1959. With this machine 15 GPs, 2 Driver Championships and 2 manufacturers World Championships were won. Evolution MV Agusta had started participating in road racing with motorcycles in the late 1940s and initially concentrated on the 125 and 500 cc classes. Piero Remor built the 125 "Bialbero" ("twin-cam") for the 125 cc class. The machine was subsequently bored to 175 cc because that class was still very popular in Italy and almost all major brands built production racers for it. The 175 cc machine was further bored to slightly above 200cc, so that in 1955 it was possible to compete in the 250cc class with the MV Agusta 203 Bialbero. After one race the capacity was further increased to 220cc. With that machine, Bill Lomas completed the 1955 season, finishing in third place in the World Championship. MV Agusta also won the constructor's title. In 1956 the machine was finally further developed into a fully-fledged 250cc racer, but that was not possible by further boring of the cylinder, so the stroke was increased from 56 mm to 60 mm. Technical The engine was an air-cooled, single-cylinder, four-stroke engine with double overhead camshafts (DOHC). The camshafts were driven by a gear train. The valves were at an angle of 90° to each other and were closed by hairpin valve springs. The bore and stroke were 72.6 mm × 60 mm, giving an engine displacement of 248.2 cc. A Dell'Orto SS 25 A carburetor was used. A Wet multi-plate was driven by gears from the crankshaft. The machine had five speeds. The rear wheel was driven by a chain. The MV Agusta had a double cradle frame that was constructed from chrome molybdenum tubes with a diameter of 25 mm × 1.2 mm. The front fork was a telescopic fork, and the rear suspension was swingarm with hydraulic shock absorbers. Results The machine was successful that year's championship: Carlo Ubbiali won five of the six GPs (in the Ulster Grand Prix he set the fastest lap but subsequently retired). Ubbiali was world champion and second in the championship was Luigi Taveri also riding an MV Agusta. MV's dominance in the 250cc class was helped by lack of competition from other factories. Moto Guzzi (third with Enrico Lorenzetti) had already stopped