Cycle News - Archive Issues - 1990's

1994 Suzuki GSXR750 • By Paul Carruthers Photos by Kit Palmer and Tom Hnatiw iz Taylor, Oprah Winfrey and Tommy Lasorda have become famous for not only their popularity in show business and baseball, respectively, but for their ability to lose and gain weight before our very eyes. Well, if these three could be transformed into motorcycles, they .would become the 1994 Suzuki GSXR750. . Once the most gaunt of all 750cc sportbikes, the GSXR of late had matured into ...well, it had become, uh fat. In 1986, Suzuki introduced a svelte 38B-pound (dry) GSXR. Last year that same GSXR750had blimped all the way up to a rotund 463 pounds. Add fluids and we're talking about a 750cc sportbike that weighs well over 500 pounds. The solution to the GSXR's weight gain was simple - it needed a good diet. Well, Suzuki's corp of engineers went ahead and put their top-of-the-line sportbike on a weight-loss program that resulted in a quick 24-pound loss over last year's GSXR. For '94, the GSXR750WR tips the scales at 439 pounds in dry form. At the very least, the weight loss comes close to including the Suzuki within the competitive range of the other sportbikes - the Honda RC45 weighs in at 416.7 pounds, the Yamaha yzf75Q has a claimed dry weight of 428 pounds, the Kawasaki ZX7-R weighs 441 pounds and the Ducati 916 has a dry weight of 429 pounds. So how did they do it? With their focus set on improving the power to weight ratio of the new bike, Suzuki's engineers analyzed what they had and then started removing things, making things smaller, using lighter materials, etc. The result was much more of a weight loss than a power gain as no changes were made to the motor to improve horsepower. The weight loss in the engine itself came from changing the breather cover, valve cover, and signal generator cover from aluminum to magnesium. The engine sprocket cover went from aluminum to plastic, and the cooling system pipes from steel to aluminum. Suzuki changed the shape of the camshaft holder caps and the connecting rods were also reshaped. Additional • holes were added to the primary driven gear and additional machining was performed on the clutch rack and pinion, on the fifth and sixth drive gears, and on the signal generator rotor. The final weight-saving alteration made to the engine was to change the transmission shafts from solid to hollow. In addition, Suzuki added mounts to the cylinder head, changed the exhaust head pipes and collectors from carbon steel to stainless steel, went to 60mm lower engine mounting bolts instead of the 55mm bolts used last year, changed the engine mounting spacers from steel to aluminum and increased the number of engagement dogs on second and sixth gear to improve gear engagement. You get the feeling, though, that the diet took the majority of the weight off the chassis. It's also obvious that this was a rather tedious task - a little change here, a little weight loss there... The frame weight has been decreased, due mostly to changes in wall thickness in certain areas. To compensate for those changes, additional braces have been added to make sure the frame's torsional strength wasn't removed along with the weight. The steering head support is now enclosed on all four sides, rather than the threesided and open design used last year; there are brackets that now attach the lower tank rails to the cylinder head of the 749cc powerplant; the upper body section is now enclosed on all four sides, while the wall thickness has been decreased; and the tank rail tube has been increased. The GSXR750's swingarm has gone to a bridged-type design (not any lighter, but according to Suzuki some 5% stronger) with the right side now featuring extruded tubing rather than the pressed aluminum construction of last year. The swingarm pivot shaft has grown in diameter from 20 to 25mm in an effort to limit flex while also reducing weight; the swingarm now also features push- type sliding bl ock chain adjusters. Since Suzuki opted to provide buyers with a bigger rear tire (170/60 ZR17 to 180/55 ZRl7), they've also had to compensate for the extra grip. They've accomplished this by increasing the rear shock spring rate some 6% while als o decreasing the spring co il diameter 0.5mm to help reduce weight. Thanks to

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