The first modern Grand Prix bike
Forty years ago this summer Barry Sheene secured his first 500cc world title. His 1976 success is memorable because it marks a high point for British motor sport, when much-loved playboys Sheene and James Hunt held the honours on two wheels and four.
Perhaps more significantly, Sheene’s campaign marked the arrival of arguably the most remarkable machine in the history of GP motorcycling. The Suzuki RG500 two-stroke won seven consecutive world titles for constructors and achieved a unique record of domination in depth: in 1976 all but one of the top 12 points scorers in the series rode RG500s, in 1977 all but three of the top 29 championship finishers rode RGs and over the following two seasons all but five riders in the first 29 rode RGs.
While Sheene rode to his first title on factory prototypes, Suzuki started selling production versions to anyone who had the money. The bike was a bargain – in 1979 a production RG cost £12,000, about £60,000 in today’s money.
Hundreds of racers bought RGs and some of them were able to run at the very front of GP events. Indeed Sheene often complained the production version was too fast, allowing talented privateers to rattle his cage and force him to take risks he could have done without. At Spa in 1977 Sheene raised the lap record to 137.15mph in his efforts to shake off French RG privateer Michel Rougerie. That race – run between rusting Armco barrier and Ardennes farmhouses – is still (and almost certainly always will be) the fastest GP of all time.
Four years later at Silverstone, Dutch RG privateer Jack Middelburg beat ‘King’ Kenny Roberts and his factory Yamaha to win the 1981 British GP. Middelburg was the last privateer rider to win a premier-class race.
The RG500 was a brilliant motorcycle, conceived by Makoto Hase, who had designed Suzuki’s 12-speed, four-cylinder 125 in the late 1960s. Like most great race bikes, it wasn’t a radical design, but rather a study in engineering pragmatism.
At its heart was a square-four engine that relied heavily on the technology stolen from East German marque MZ and its genius engineer Walter Kaaden, who had worked on Hitler’s secret weapons programme during the Second World War.
While Yamaha used an inline-four two-stroke, Suzuki chose a square-four format, essentially two of Kaaden’s tandem 250 twins in a common crankcase. One of the cornerstones of Kaaden’s technology was rotary-valve induction, which fed directly into the crankcase. The RG’s narrower square-four layout had the four carburettors mounted either side of the engine and delivered excellent mass centralisation, which was a major factor in the bike’s neutral handling.
Sheene had his first ride on an early development RG at Suzuki’s Ryuyo test course in early 1974. Inevitably, the bike was far from right. “That first RG started running at nine thousand rpm,” said Sheene in 2002. “Below that there was nothing, and when I say nothing, I mean nothing. To get it out of the paddock you had to scream it to 10 grand or it wouldn’t even clear, and it stopped at ten-five, so once you’d got it clear, you had a thousand rpm to play with. I told them it was a waste of time unless they spread the powerband, but they were going ‘Barry-san, it’s got 105bhp!’
“Foolishly I told Suzuki I’d go to Japan at the end of ’74 and stay until the engine was right. I was there five weeks, the biggest jail sentence I’ve ever served, but the bike came good.”
Sheene won the RG’s first GP victory at Assen in June 1975 and the Mk1 production RG was immediately competitive when it went on sale in February 1976; so much so that the bike gave 15-time world champion Giacomo Agostini a very rude awakening during a pre-season tour in Australia.
“Ago probably expected a fairly leisurely time on his MV Agusta and a bit of easy money, as in previous years,” recalls Jeremy Burgess, Valentino Rossi’s former crew chief, who raced an RG in Australia before moving to the other side of the pit wall. “But Ago was bombarded – he got taken to the cleaners by a bunch of production two-strokes.
“The RG was fantastic to ride. I could only put it into context when I got rid of the RG and bought a TZ750 Yamaha. I thought the TZ would be better but it didn’t have the same feeling. With the RG you felt you were sitting in the bike, with the 750 you were sitting on it.”
However, the RG’s performance had a price: fragility. “You really had to have a bit of an engineering brain, an understanding that maintenance was very important,” Burgess adds. “If you expected to just run it week after week, which you could do with the Yamaha, you’d end up with some expensive repair bills.
“There were a few weak spots. You had to keep a constant eye for cracks in the rotary valves. It was frustrating when things broke but I learned that if you can see the crack before something breaks, the bill will be smaller.”
Factory RG500s won the 1976-77 titles with Sheene on board and the 1981 and 1982 crowns with Italians Marco Lucchinelli and Franco Uncini. Sheene scored the bike’s final GP podium in South Africa, almost exactly a decade after he had put an RG on the podium for the first time at the 1974 French GP.
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