GSX-R : The First Generation

source : wikipedia

The first generation of GSX-R of 1984 was a breakthrough model and the closest that any Japanese manufacturer had yet come to building a "race bike with lights". Throughout the 1970s the big four Japanese manufacturers had built bikes with a similar architecture: steel double loop frames, air-cooled inline fours with either SOHC or DOHC configurations.

At the start of the 1970s two valve per cylinder heads were ubiquitous, by the end of the decade four valve heads were available on the high end bikes. The similarity of the designs across brands and years led to the coining of the term "UJM" for Universal Japanese Motorcycle, which began with Honda's CB-750 of 1969.

These bikes were available in a variety of sizes from 350cc to 1200cc from all four of the Japanese manufacturers, and beginning in 1976 served as the basis for production-based race bikes in the American Motorcycle Association (AMA) Superbike Series. As a result of the experience on the race track it became obvious that the big UJMs were not ideal for racing. Weight was high, frames lacked stiffness and flexed in disturbing ways, power from the big motors overwhelmed the tire technology of the day.

Beginning around 1980 all four manufacturers began to modify the UJM formula in different ways to achieve performance advantages on the track and product differentiation in the market. In 1982 Honda introduced the VF series, which used a V4 rather than inline-four motor configuration. The first model year only cruiser style bikes were offered, but in 1983 the first sport bike based on the V4 became available:the Honda VFR-750 Interceptor. AMA rules for Superbike racing were changed in 1983 to decrease maximum engine size from 1025cc to 750cc. The Honda Interceptor was ready to compete in this new category. In addition to the innovative V4 engine configuration, it was liquid cooled, and it sported a rectangular tube steel frame, to increase stiffness, as opposed to the more traditional round tubes of the UJM era. The Interceptor was a breakthrough for Honda, and it won many races,including Daytona, and was the second-place finisher in the series. A year later, in 1984 the entire front row at Daytona were Interceptors and Freddie Spencer repeated his win on the V4 Honda.

In 1985 both Yamaha and Suzuki answered the challenge with their own innovations. Yamaha offered the FZ750 which was the first in a series of bikes with 5 valves per cylinder. While it was still an inline 4, the cylinders were set at a 45 degree angle, unlike the more typical nearly vertical placement common to UJMs. The frame was rectangular section steel like the Honda.

It was into this competitive environment that Suzuki dropped the first 750cc GSX-R model ready to race in the new size mandated by AMA Superbike rules. The GSX-R had the most conventional engine of the three: a four valve per cylinder, inline four - it was a clear descendent of the previous GS series of motors. Cooling was provided by what Suzuki described as an air-oil mix. Oil temps were kept low by a large oil cooler, and engine internals were designed to push the oil at pressure as a spray where it was most needed, notably the underside of the pistons. The principal designer for the bike was Hiroshi Fujiwara, a Suzuki engineer.

GSX-R 1985

The frame was the most innovative aspect of the bike. Suzuki abandoned steel altogether and built the frame from welded square section aluminium tubing. To gain the rigidity they wanted, the tubes were quite large, giving the bike a unique appearance. Whereas the Honda and Yamaha were fast street bikes that could be easily raced, the Suzuki was clearly a race bike that could be ridden on the street. The seating position was the racer's crouch, not the street rider's semi-upright one. It shipped stock with the motor tuned to deliver 100HP, but could be easily boosted to 135 with the race tuning kit. It was the lightest of the superbikes by a good margin, weighing only 388 lbs. Styling too was aggressive and unique, with a signature full fairing holding two round headlights, starting a trend that continues on supersport motorcycles to this day.

Despite the excellence of the bike it was not able to immediately dethrone the Honda team, who won the AMA Superbike series with the VFR Interceptor from 1984 to 1988. In 1989 Suzuki did accomplish this goal. By then the Suzuki had already become the favorite of privateers, racers not backed by a factory. Its relative simplicity (compared to the V4), cost and reliability made it the obvious choice for individuals competing on their own dime. Over time it has also established an excellent record in endurance racing winning the Bol'd'Or 12 times between 1993 and 2011.

The 750cc GSX-R of 1985 was followed by an 1100cc version in 1986. If the 750cc bike was a fast and capable race-bike for the street, the 1100 was an exercise in raw power and excess. A bit heavier than the 750, at a claimed 435 lbs, but with considerably more power (130 hp stock) and torque. Previous to both of these models, 1984 Suzuki released the GSXR400 (internal model number GK71b), on sale only in Japan, taking advantage of licensing laws there which were prohibitive of bikes over 400cc.