“A Legend Now Begins” was how Suzuki’s publicity heralded the introduction of the GSX-R750 Hyper Sports in 1985, and for once the publicists got it right. Few motorcycles have emulated the impact of the GSX-R750, a motorcycle that has set a benchmark for affordable production sporting motorcycles for decades.
Before the GSX-R there were no real racing derived street Japanese motorcycles. Although the Japanese had ruled the racetracks for more than twenty years, somehow this didn’t translate into production machines. During the 1970s the Japanese couldn’t see why street motorcycles needed clip-on handlebars and rear-set footpegs.
Although the Italians were adept at producing expensive limited edition production racers, the GSX-R 750 was the first widely available race replica motorcycle since BSA’s Gold Star of the 1950s and early 1960s. For the first time in two decades here was a motorcycle the average punter could ride at the track and ride home afterwards. As the first pure race replica from the Land of the Rising Sun, the GSX-R750 also created a subculture that continues today.
What really set the GSX-R750 apart from other 750s in 1985 wasn’t exceptional power, but an outstanding power-to-weight ratio. The target was only a fairly moderate 100 horsepower from 750 cc, but in an era where the average 750 cc motorcycle weighed 220 kg Suzuki aimed for a maximum weight 20 per cent lighter, at 176 kg. To achieve this Suzuki eschewed water-cooling with all its associated plumbing, preferring oil cooling, and a new ellipsis – SACS, or Suzuki Advanced Cooling System.
The lower operating temperatures allowed by oil-cooling, compared to straight air-cooling, allowed for many lighter internal components. At 70×48.7 mm the engine was also extremely oversquare, with the regulatory double overhead camshafts and a four-valve cylinder head with a new version of Suzuki’s TSCC (Twin Swirl Combustion Chamber).
Another distinguishing feature was the number of acronyms, most proudly emblazoned on the bodywork.
Feeding the cylinders were four flat-slide Mikuni 29 mm carburettors, exiting through a four-into-one exhaust system. A six-speed gearbox kept the high revving engine on the boil. To minimise engine width the alternator was relocated from the end of the crank to the top of the crankcase behind the cylinders.
Although the power was a moderate 104 horsepower at 10,500 rpm, the engine unit only weighed 73 kg. Unfortunately the quest for extreme lightness resulted in some components built at their design limit and early engines were a little fragile, at least by Japanese standards.
To quell any question of unreliability Japanese engines in the 1970s and early 1980s were conservatively built. They were strong but heavy. With the GSX-R 750 Suzuki took a different path. With Japanese reliability no longer in question they erred on fragility at the expense of long life.
It is no coincidence that you rarely see an early GSX-R around these days, and those that do command a premium price.
The frame for the GSX-R750 was closely modelled on that of the works endurance racers and was the first aluminium alloy frame to appear on a mass-produced street bike. Designated MR-ALBOX (Multi-Rib Aluminium Alloy Box Section), this weighed around 8 kg, but was prone to flex under racing conditions.
Race track handling was the GSX-R’s raison d’être, and a banking angle of 55 degrees, wheelbase of 1,435 mm, and a stout 41 mm cartridge fork saw to that. To maintain a low seat height the Suzuki Full Floater rising rate rear suspension was revised with an eccentric cam. The braking was also state-of-the-art for 1985, with four piston front brake calipers gripping 300 mm discs.
The rear twin piston caliper incorporated an anti-hop torque tube. The only unexpected feature were the 18-inch wheels front and rear. Most manufacturers at this time were experimenting with 16-inch wheels but as Suzuki’s endurance racers used 18-inch rims so did the GSX-R750. Although an 18-inch front wheel slowed the steering, the GSX-R made up for it with a steep 26-degree fork rake.
The original GSX-R750 was a milestone motorcycle, the bike that allowed everyone to share the experience of a racing bike on the street. With its emphasis on minimalism and lightness there was no more focused and affordable high performance motorcycle available in 1985. It was also the first in a long line of GSX-R race bred Suzukis that continues today. And as with so many modern collectables, the first edition is the one to have.
Ian Falloon is the author of more than 45 books that cover a variety of brands and motorcycle models. He has recently updated his Ducati 750 GT to now describe a rare 1973 version that he had not seen before.
This new edition is available to order for AUD$120 (free worldwide shipping) payable to PayPal.me/ianfalloon. For all those who have already purchased this book, Ian is providing a high resolution PDF free of charge of the new edition.
Australia’s go-to-guy for classic motorcycle wisdom. Ian has written nearly 45 books on motorcycles that each offer unparalleled insight on the historical and technical development of particular makes and models.