The other Japanese factories were just as innovative, with Suzuki developing their water-cooled 14-speed 50cc two-stroke RK67 twin in ’67, and a remarkable 125cc V4 that produced 42bhp and needed a 12-speed gearbox to keep the revs in the 500rpm-wide powerband. Yamaha stuck with two-stroke twins until it became obvious that they’d have to play catch-up, and in 1965 produced race-winning 125cc and 250cc two-stroke V4s. But with the complexity came huge costs, and the door slammed shut in the late 1960s, when regulations limiting the number of cylinders to one, two, or four, depending upon the class, and gear ratios to just six per box, were imposed.
But the prize for the most ambitious project of all must go to Moto Guzzi, for the 500cc V8 Grand Prix racer they built in just a few months before the ’55 season – the Otto Cilindri. With both MV Agusta and Gilera racing four-cylinder machines, Guzzi’s 500 single had passed its use-by date, and designer Giulio Carcano wanted to crush, not just match, his Italian rivals.
Carcano started scheming after the Spanish Grand Prix on 3 October 1954, where Australian rider Ken Kavanagh slotted his ageing Guzzi 500 single in between two MV fours for second place. An in-line six, the Italian reasoned, would be too wide, but a V8 with four small cylinders per bank mounted across the frame could be narrower than an in-line four with bigger bores.
Moto Guzzi’s racing department consisted of just 11 people, but the new engine ran for the first time just three months later. The 500cc water-cooled four stroke V8 boasted twin overhead camshafts for each bank of cylinders, eight sets of points, four ignition coils, two six-volt batteries, eight 20mm Dell’Orto carburettors, and eight open exhausts, sans megaphones. The engine used a four-speed transmission, but could accommodate another two ratios if necessary, and the rev ceiling was set at 12 000rpm. Initial output was 62 horsepower, which grew to 80bhp over the next three years. The bike weighed in at 148kg.