MULTI-CYLINDER MADNESS

By Gavin Foster

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So you think Grand Prix bikes are complex now? To see some really trick kit, you need to go back in time to the 1950s and ʼ60s. Today the manufacturers and outside sponsors all pay super-fit young professionals millions of dollars to ride their remarkably similar machines as fast as they can in circles around ultra-safe racetracks. Top racers a few decades ago battled to scratch out a living and often rode in three classes on a single day, just to earn enough start money to survive upon. There were no outside sponsors, and the works teams poured most of their cash into developing exotic machines rather than paying their riders decent money. The tracks, many of them public roads, were extremely dangerous, and half a dozen good GP riders died every year simply trying to pay the rent.

Before 1969 there were no restrictions on the number of cylinders or gears used by GP machinery, so some extraordinarily complex racing machinery saw the light of day. The Italian MV Agusta and Gilera threes and fours did battle with single-cylinder British thumpers that acquitted themselves surprisingly well in the ʼ50s, but the Japs upped the stakes considerably in the ʼ60s by bringing all sorts of astonishing toys into play. In November 1963, at the very first Japanese Grand Prix at Suzuka, Honda surprised the opposition by rolling out their RC114 – a 170km/h twin-cylinder 50cc four-stroke that used ten gears and more than 20 000rpm to deliver 15bhp to the tar – at 300bhp per litre, that’s perhaps 15% more efficient than a modern MotoGP machine. This was followed by the fabulous 250cc Six, and, in October ’65, a marvellous little five-cylinder 125cc four-stroke that could top 220km/h.

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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.

Considering that there were no computers available in 1954, Carcano’s achievement was remarkable. According to an article in a 1972 Cycle magazine, the carburettors were fine-tuned by running the engine in a darkened room and observing the red-hot glow of the exhaust pipes. Moto Guzzi’s success in the machine shop did not, alas, translate into racetrack success, due to endless reliability problems, but the V8 was certainly quick. It achieved 300km/h on the Mira test track and was clocked at 285km/h during the 1957 Belgian GP, where Keith Campbell took the lead, smashed the lap record time and again, and then retired when a battery cable broke. The same year, Dickie Dale finished 4th in the Senior TT, with the bike running on seven cylinders, and won a non-championship race, the Imola Gold Cup, on the Guzzi. But in the Grand Prix races water pipes burst, wires came loose and victory remained elusive. The end came after the ’57 season, when Moto Guzzi retired from racing, perhaps a year too soon.

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The bikes raced today produce more than enough power, and nobody wants to be lumbered with extra weight, so we’re unlikely to see or hear another V8 howling down the straight. You can still listen to the Guzzi, though – pour yourself a stiff drink and Google ‘Moto Guzzi V8 sound’ – you'll come across a number of websites with video and audio footage of the old racers.

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