MV Agusta 350/6 four-valve prototype
With Phil Aynsley
MV Agusta’s first six-cylinder race bike was the 500/6 of 1957 but a 350cc version was also envisioned. The prototype (which as with the 500/6 used a two-valve head) made a single appearance – in practice at Monza at the end of 1957.
Ten years later Count Agusta followed Honda’s lead (they had won the ’67 350cc championship with Mike Hailwood on the 297 cc six-cylinder RC174) by having his engineers dust off the old 350/6 drawings and constructing a modernised version.
The same DOHC design, but with four-valve heads and oil-cooling, was employed. A seven-speed gearbox and six Dell’Orto SS16 carburettors were fitted. The end result was a bike that made 75 hp at 16,000 rpm, had a dry weight of 149 kg and a top speed of 250 km/h. Hailwood tested the bike at Monza in 1968.
Agostini was against the development of the 350/6 due to its weight and width hindering his riding style. As a result Angelo Bergamonti was drafted into the team to develop the bike which underwent a prolonged testing regime that was terminated after Bergamonti’s death during a street race at Riccione in 1971 (which ended street circuit racing in Italy).
The sole 350/6 constructed is now owned by ex-factory employee Lucio Castelli and is demonstrated regularly. The images of the bike here were taken at the Phillip Island Classic in 2003. The shots of the cylinder head were taken at the Elly Collection in 2013.
