The Champ And The Kid
A Look At The Bike That Started A Revolution
By David Swarts
“Lighter is better” seems to be the latest big thing in sportbike design. In the rush to embrace this recent “new” trend toward lighter and lighter sportbikes, it’s easy to forget that shockingly low weight was a key feature of the 1985 Suzuki GSXR750, a bike brought to life under the direction of Etsuo Yokouchi and credited with creating the racer-replica category. Although most of the world got the GSXR750 in 1985, the United States had to wait until 1986. The 2000 GSXR750 therefore marks the 15th anniversary of the model line in the U.S. Over the years the GSXR750 has taken over 750cc production-based racing and has now been re-born stronger than ever to start a new century of competition on the racetrack and the dealership floor. Roadracing World decided to re-visit this historic line of motorcycles from behind the bubble, taking a fleet of various year-model GSXR750s to Henderson, Texas’ Oak Hill Raceway with former 500cc World Champion Kevin Schwantz, now 35 and originally from Houston, and new young gun Ben Spies, 15, from Longview, Texas. Comparing the perspective of the champ and the kid should prove enlightening. “The main concept of this machine is born on the circuit, and returned to the circuit,” were the words of Yokouchi. Yokouchi was a strong advocate of racing and high performance, and his design team set out to take what the company had learned through racing, particularly endurance racing, and apply it to a revolutionary streetbike. Yokouchi was also well known for demanding perfection from his design team and for rejecting design details that didn’t meet his expectations.
Aluminum frames were already around in the early 1980s and in theory an aluminum frame was lighter and stronger than the steel-tube units that were the status quo. The problem was producing an aluminum frame that could handle relatively high horsepower and in a cost-effective manner. Suzuki engineers learned to incorporate aluminum castings along with extruded tubes to reduce the number of parts needed to make a frame from over 90 on a steel example to 26 on the GSXR750. Suzuki’s engineers also developed their own unique alloy, which eliminated the need for a final heat-treating process. In 1983, Suzuki produced the first production bike with an aluminum frame, the two-stroke RG250. In 1984, Suzuki followed that up with the domestic-market, alloy-framed GSXR400. Then, at the 1984 IFMA motorcycle show in Cologne, the world got its first look at the GSXR750.
This drawing shows how a high-volume flow of oil was routed through
the cam case and across the top of the combustion chambers,
carrying away heat.
To contrast Schwantz’s vast racing experience overall and first-hand knowledge of several GSXR750 models, we picked one of the youngest professional racers anywhere. At 15 years old, Team Valvoline EMGO Suzuki’s new signing Ben Spies is about as young as they come. Spies’ credits include several CMRA regional Championships, several CMRA lap records, the 1999 WERA Formula Two National Championship, and limited experience on production-based racers. Beyond that, Ulrich says that Spies has the same type of natural talent that caught his eye when he first saw Schwantz in 1984.
plotting his AMA Supersport debut. The only catch is that he’d have to wait until he turned 16.
down the hill leading into turn five at Oak Hill Raceway.
Spies was not yet born when this 1986 GXR750 was built.
Owner Wilson enjoyed watching Schwantz ride his bike, saying, “It’s exciting. I’m enjoying it. I’m enjoying watching him on the bike. There’s nothing like meeting a 500cc GP World Champion face-to-face, then having him ride your bike on the track.” Wilson’s bike was in stock, street condition except for a Yoshimura exhaust, a jet kit, a steering damper, and Avon tires on the 18-inch wheels. Suzuki engineers completely re-thought every bolt of the GSXR750 for 1988. They started with a new frame to replace the old unit, which was prone to flex too much under racing conditions. In fact, Schwantz’s 1988 GSXR750 Superbike’s frame had pieces from another GSXR’s frame cut and welded onto it to serve as bracing. The 1988’s new frame was patterned after the 1987 Suzuka 8-Hour racebike with the upper beams being thicker and splayed wider. The steering stem grew from 60 to 80mm while the swingarm pivot was now cast into the frame instead of welded on. The larger 43mm forks featured “..more adjusters than an insurance convention,” according to Cycle World’s Paul Dean. A first for a mass-produced streetbike, the forks featured adjustments for spring preload, compression and rebound damping in a time when most bikes were lucky to get forks with adjustable air pressure. The GSXR750J-model’s chassis also featured a new gas-charged rear shock, a more progressive shock linkage, a 2.0-inch shorter wheelbase, and steeper steering geometry. The highlight of the new chassis had to be the huge-for-the-day, 3.50-inch front and 4.50-inch rear 17-inch hollow-three-spoke wheels, with Michelin Hi-Sport radial tires developed specifically for the GSXR750.
The new frame cradled a new short-stroke engine. The bore/stroke went from 70×46.7mm to 73×44.8mm. The redline went to a sky-high 13,000 rpm, higher than Schwantz’s 1987 Superbike’s motor spun! Changes included a bigger airbox, a new Suzuki Condensed Air Intake (SCAI) system feeding fresh air to the airbox, bigger valves, new cams with more lift and duration, higher compression, 36mm “Slingshot” carbs (up from 34 mm), dual-electrode spark plugs, a new digital ignition, a 4-into-2 exhaust system, more oil capacity, a larger oil cooler and higher-flow oil lines for improved cooling, and it all worked to raise power to 90 horses. The new powerplant was moved 12mm lower to reduce the center of gravity. A new fairing reduced drag by a claimed 11 percent with internal streamlining to help keep the rear shock cool. The wider frame allowed the reshaped gas tank to carry the same amount of fuel, but lower. The new bike was 3.3 inches lower from the top of the fairing bubble to the ground. The result was a motorcycle that looked and felt more compact, made much more horsepower, but weighed a whopping 40 pounds more. The extra weight came from the engine (11 pounds heavier), frame (15 pounds heavier), plus the wheels, tires, and exhaust. Suzuki engineers felt that the added weight was necessary and worth it, given the much improved chassis. In fact, the extra weight actually lowered the power-to-weight ratio with the ’88 versus the ’86. Unfortunately, the new chassis had a lack of cornering clearance even at a moderate pace on the street, and it was hard to improve the engine’s power output to race levels.
The lower engine position, the new exhaust, the extra weight, the 17-inch wheels and lower- profile tires all contributed to the lack of cornering clearance. The band-aid fix was maxing out the shock’s spring preload, but this forced a compromise chassis set-up. The racer fix was to fit a 4-into-1 exhaust with a high pipe, pulling the fairing lower in tighter if not removing it altogether, and most importantly, fitting a shock with adjustable ride height. With the original long-stroke configuration, the Suzuki made decent low-end and midrange power out of the box. Race tuners quickly were able to develop the top end power that they wanted. The new, more oversquare motor came with a top-heavy powerband and little else. Unfortunately, engine builders were not able to tune the new motors to the power levels of the old long-strokers, and to make matters worse, the combustion chambers were prone to cracking and losing pieces of aluminum around the valve seats. But although he was down on power on the Daytona banking, Schwantz felt the new chassis could make up the lost time and then some through the infield and the old, short chicane. Schwantz took the Pole and won the 1988 Daytona 200 in his last AMA Superbike ride. (In the last 20 years, Suzuki has won the Daytona 200 exactly three times. In 1981, Wes Cooley rode a GS1000 to victory. In 1988, Schwantz got the job done. Mat Mladin made it three this Spring.) Also in 1988, Doug Polen won the AMA 750cc Supersport Championship, the GSXR750’s first. Polen was followed in the 1988 750cc Supersport points standings by a fleet of Team Hammer Support riders, including Scott Russell, David Sadowski, Russ Paulk, Mike Harth and Jamie James. The February 1988 issue of Cycle reported “�the new bike did everything more quickly and easily than the old: Stop, go, turn and drag the ground,” adding that the bike “�really forces a compromise between optimum suspension settings and maximum ground clearance.” For the third year, journalists complained about the racer crouch seating position and engine heat getting to the rider.
However, the GSXR750 often got better street ride rankings for its very adjustable and compliant suspension and wide seat.When I asked Steve Findley how he deals with the ground clearance problem on the 1988 GSXR750 he brought to Oak Hill for our track day, Findley said, “I put a different shock on it, but mainly I lay it over until I see sparks. That’s as far as it’s going over. It handles real well for what it is. It’s a lot of fun to go out and ride. It still makes good power. I’ve got a newer one to race, and this one to play on.” Findley regularly races his GSXR750 with the CMRA. So it was no surprise that this machine featured some race hardware including Michelin Pilot tires. After riding the 1988, Schwantz said, “It feels a little bit different than the ’86. The biggest improvement between the two is the power. This bike feels more like a racebike. It doesn’t have that plushy, streetbike-ish feel. It works well. No problems getting around out there. I think my knee even hit the ground a few times. It does remind me of the ’88 that I used to win the Daytona 200. From the ’87s to ’88s, the bikes that my teammates were racing anyway, the ’88 had a little different feel to it. It was more aerodynamic. I think that paid dividends in the 200. This bike was all pretty respectable. I wouldn’t mind racing it for a weekend.” Spies added, “It was a lot different that the ’86. It was more jacked-up in the rear, It felt good. It handled good. I was having fun on it. The higher rear end made it steer quicker than the ’86. It felt more like a modern racebike. It was probably a little heavier than the ’86, but I wouldn’t guess by much. I didn’t really feel it out there. The ’88’s power range was smoother. This bike didn’t feel that far from my racebikes.”
Here, young gun Ben Spies confers with former World Champion Schwantz.
The complaints about the ’88’s ground clearance problem were so severe that Suzuki engineers reacted in the very next model, the 1989 GSXR750K. For $600 more ($5799), Suzuki engineers moved the shock’s top mount 4 mm lower and installed 6 mm longer fork tubes to relieve clearance problems. Stainless steel covers for the exhaust canisters, revised transmission gear ratios, a lower secondary gear ratio, a four-way adjustable brake lever, and a competent challenger from Kawasaki were all new for 1989. In Cycle World’s July 1989 comparison, the GSX-R was cheaper, 14 pounds lighter, slightly stronger on the brakes, had a much better suspension, and won. Kawasaki’s engine, however, produced a wider, more forgiving powerband. Kawasaki’s first shot at the GSX-R came pretty close to the mark, but then again, they had three years to take aim. The 1989 GSX-R continued to perform in the hands of racers. Jamie James won both the AMA Superbike and 750cc Supersport Championships for Yoshimura Suzuki. Doug Polen won the 1989 All Japan F1 Championship on a GSX-R as well.
From first glance, the 1990 GSXR750L-model didn’t appear to be much changed. An enthusiast might notice the new stainless 4-into-1 exhaust and the rear shock’s remote reservoir. The truth was that the bike was thoroughly revised from 1989. The frame was improved again. The main sections were splayed wider while the steering head braces, running to the front frame downtubes, were repositioned to make room for a new, larger oil cooler. A longer swingarm with thicker walls was also added, extending the wheelbase from 55.1 inches to 55.7 inches. The rear wheel grew to 5.50 inches in width and the rear tire from 160 to 170. Suzuki engineers had to lengthen the transmission output shaft by 3mm to get the chain around the new tire. The rear shock not only got the reservoir but a new aluminum body and more adjustability. The front rotors were now slotted and thicker instead of drilled and thinner. The biggest news was that Suzuki engineers had gone back to the original, long-stroke engine layout for 1990 while maintaining the short-stroker’s power and redline. Piston speed was now up to where only racing motors had dared to go before, but Suzuki engineers had learned a lot about how to make connecting rods since 1985. Now, the rod bolts threaded into the rods themselves rather than using an external (and heavier) nut and bolt arrangement. The new rods, as with many of the 1990’s parts, were carryovers from Suzuki’s limited-edition 1989 GSXR750 RR. Included in those parts were smaller, lighter pistons than in the 1986/1887 with a new Alumite coating. The combustion chamber now had a more domed shape. To help prevent cracking of the area between valves, spark plugs shrunk to 10mm. The oil cooling system was once again improved. A curved oil cooler from the GSXR1100 allowed more surface area without more frontal area, increasing heat dissipation by 48 percent. A new, deeper oil sump helped prevent windage loses. Suzuki’s 49-state GSXR750s got 38mm carbs (California models had the same 36s) with a non-functional power jet that tuners soon made functional. The new 4-into-1 pipe improved ground clearance but definitely restricted power. The $6199 1990 model made 11 percent more power than the 1986 and weighed 6.0 percent more. The GSXR750L-model weighed 494 pounds fully wet. In the hands of journalists, the 1990 GSXR750 broke into the 10-second bracket at the drag strip while topping 150 mph on a long-enough road. The GSXR750’s main competition was again the Kawasaki ZX-7, but magazines regularly tested these two against the expensive, limited-edition Honda RC30 and the non-U.S.-legal Yamaha FZR750RR/OW01. Even in this lofty company, the Suzuki usually won high praise on the street (for suspension compliance, not ergonomics) while turning the quickest time in the quarter-mile for the least amount of money. With Kawasaki inching closer, Suzuki began to stumble in 1991. The 1991GSXR750M looked very different from the outside. The all-new bodywork grabbed a lot of attention. A slimmer tailsection and headlight cover reduced drag by a claimed 2.3 percent. The Suzuki’s inverted Showa front forks were a first on any streetbike and were credited with better handling especially under braking. Another change worth noting was made inside the cylinder head. From a set-up with a single cam lobe and single forked rocker arm actuating a pair of valves, Suzuki went to individual cam lobes working individual rocker arms. The old forked rockers were now considered too massive while being too flexible at very high rpm. Valve lash went from being adjusted by heavy screws on the rocker arms to small, simple shims.
1991 GSXR750 the longest. The holes in the fairing on this example carry
projector head lamps for street riding.
The engineers also revised porting, installed the GSXR1100’s stiffer valve springs, reshaped the combustion chamber, and changed cam timing slightly. After all this work, Suzuki claimed no power gain, only that peak power could be held for longer with better high-rpm control of the valve timing. The ’91 did gain a few horsepower, now up to 94-ish, saw 2.0 more mph in top speed, no improvement at the drag strip with Cycle World at the controls, but more importantly gained another 20 pounds and now weighed 514 fully fueled. Where did the weight come from? The new bodywork, the new forks, the glass headlight cover, an OEM steering damper, and the reinforced frame downtubes. The Suzuki was now the heaviest bike in its class behind the Kawasaki ZX-7, ZX-7R, and the Ducati 851. Still, the Suzuki was second to only Kawasaki’s expensive limited edition ZX-7R in terms of power and quarter-mile times and won Cycle’s comparison on the strength of its street manners and lower price over the second place ZX-7R. Cycle reported, “�the least expensive bike in this test is also the most impressive,” and “�it remains the weapon of choice for the street, offering superior suspension performance, and near-parity in acceleration with the class’ hardest runner, all in the class’ best-rounded, and most accessible package.” That same ZX-7R marked an end to Suzuki’s dominance in AMA 750cc Supersport racing. Starting in 1990 through ’91 and ’92, Kawasaki’s Scott Russell and Doug Chandler went on a 26-race winning streak. Yoshimura did not even bother to field a team in 750cc Supersport in 1991 or 1992. Our 1991 test bike, an ex-endurance racer now retired to the street, was provided by CMRA racer Chuck Catlett with a motor by Tracy LeBlanc. The bike featured high compression pistons, a Fox shock, pipe, jet kit, and some shagged-looking Michelin slicks. Schwantz gave the slicks a long look before heading out onto the track.As Schwantz rode each of the bikes, the owners would just glow like proud fathers.
Catlett was no different, saying, “It’s absolutely wonderful to have Kevin Schwantz ride my bike. I didn’t realize it was so fast. He and Ben have been saying good things about the other motorcycles so far. I’m just keeping my fingers crossed that they’ll say something good about this one.” Schwantz knew that we weren’t concerned with lap times and was riding casually fast most of the day. However, Schwantz took extra time getting up to speed on the ugly tires. But once up to speed, Schwantz kept the ’91 out for the longest. The thinner-than-you-think Schwantz came in finally and said, “It’s definitely a different feel than the ’86 and ’88. It feels like you’re sitting more on top of everything. You’re not sat down into the bike as much. It’s a little bit different feel. It took me a while to get comfortable with it. All-in-all, it feels that there’s been improvement as the bikes have progressed. It feels like this bike could do more of what you wanted once you really started to ride the thing hard. It’s more of a comfortable, modern-day feel as to you sitting on top and maneuvering it a lot better. I was pretty happy. I didn’t really notice any increase in weight. Maybe it helps here at Oak Hill, a little heavier bike helps soak up those bumps a little better. Maybe that’s why I was more comfortable on it, too. Each bike has its own little things that it does good. This one feels better on the brakes than the ’88 that I rode. They didn’t have the initial bite, but they felt like they would stop you quicker more comfortably. The inverted forks could very possibly have helped the feel on the brakes. I like the suspension on this bike. The ’88 may have been a little harsh for me. I liked the feel of this bike as much as the ’86. The rear tire was a little bit greasy, though.” Spies’ comments weren’t quite as detailed. The teen said, “The ’88 and ’91 weren’t two totally different bikes. They both handled about the same. The ’91’s power came on a little lower. It didn’t hit as abrupt as the ’88’s power. The brakes I thought were about the same. This bike wasn’t farther away from the ’86, and it wasn’t much closer to my bikes. I still like my ’99 racebikes the best.” While the world got a water-cooled GSXR750 in 1992, the U.S. had to make due with bold (and I do mean bold) new graphics, an unintentional power increase to near 100, a $200 higher price at $6699, and an overweight and under powered liquid-cooled GSXR600 little brother. There had been meetings at Suzuki about a radical redesign to a twin-spar frame/downdraft carburetor layout, but the proposal was reportedly shot down by marketing guys saying that it would be a “me too” design and “it wouldn’t look like a GSX-R.” I wonder where those guys are now. In their defense, the GSX-R was still selling well. The 1993 U.S. model went through a major change. Finally, Suzuki engineers gave up their losing battle with the heat-versus-power trade-off and went to water-cooling. The results were actually less horsepower in street trim, more power in race trim with a successful return to 750cc Supersport racing, and the heaviest GSXR750 ever. Suzuki engineers didn’t just abandon their much-beloved oil cooling, though. (In fact, Suzuki has current streetbikes with engines derived from the original GSXR’s oil-cooled engine.) They retained the first stage of the oil pump that circulated oil through the engine as well as sprayed the undersides of the pistons. The rest of the cooling system was over-engineered to help racing efforts which had been hurt the most by the oil cooling system’s shortcomings. The new cooling system had twice the cooling capacity of the 1992 model’s air/oil-cooling system. Suzuki engineers worked hard to upgrade and take advantage of the cooling system. The valve train lost its rocker arms altogether now, letting the cam lobes work directly on valve buckets. The included valve angle was narrowed to 32 degrees from 40. Better heat control let the compression ratio rise to 11.8:1 from 10.9:1. The pistons got lighter, and the valve stems grew slimmer. The engine was narrowed by 57mm thanks to reduced cylinder pitch (the space between the bore centers), a shortened crank, and a new gearbox using narrower, large diameter gears riding on finer pitched shafts. The smaller engine could now be mounted lower to improve the center of gravity and front weight bias without the fear of ground clearance problems.
Besides having water cooling, the 1993 model also set a record for GSXR750 weight,
weighing over 550 pounds fully fueled.
Once again Suzuki engineers tweaked the chassis. A new pentagonal-section frame increased rigidity 5.0 percent. A new asymmetrical swingarm was more rigid while allowing the exhaust pipe to tuck up for more ground clearance. The aluminum subframe was now removable. The steering geometry was quickened while the wheelbase was lengthened. Suzuki brochures claimed that the frame and swingarm were lighter, but the GSXR750’s weight was now 553 pounds wet, a full 100 pounds more than the original 1986 GSXR750 and the 1993 Honda CBR900RR released just a few months before! The new bike was fundamentally identical to the 1992 GSXR600 which was itself basically a de-bored 1993 GSXR750. It cost $7299 to have a water temperature gauge on a GSXR750 in 1993. Unfortunately, the Suzuki men didn’t get much in the way of results for their efforts. Power was down about 5.0 horsepower, to 95. Most tuners felt the culprit was in the cam timing. Other rumors said that there were problems with the new single-spring valve train forcing the bike to be de-tuned at the factory. Yoshimura’s tuners liked the bike just fine and returned to 750cc Supersport racing to win the 1993 AMA Championship with rider Britt Turkington’s four wins and nine podiums. AMA Superbike pilots Donald Jacks and Thomas Stevens had less fun. Stevens said, “I’ve never ridden so hard to go so slow.” In a 1993 comparison between the Yamaha YZF750SP, the Kawasaki ZX-7, and the GSXR750WP-model, Cycle World wrote, ” The Suzuki’s dyno numbers are a disappointment,” and “�liquid-cooling has not brought an increase in performance. Even with its power deficit, the GSXR wasn’t that far off the pace�” and “�on the street, its suspension was the most comfortable. The ZX is quicker, faster, better on the racetrack than the GSXR, and easier to ride at speed.” The YZF was excluded from the results because it wasn’t available in the U.S. yet.
cradle-type frame to the twin-perimeter-spar frame introduced for 1996.
Here, Ben Spies rides a 1993 with a cradle frame while
Kevin Schwantz tries a 1999 with a spar frame.
Randy McSpadden’s 17,000-mile 1993 GSXR750 was one of the cleanest and closest-to-stock of all of our test bikes. The only non-standard parts were EBC brake rotors from Marietta Motorsports to replace the warped stockers. Schwantz went first and came back, choosing his words carefully, to say, “It felt the heaviest of everything I’ve ridden so far. It’s hard to get it to fall off into the corner. It wants to stay stood up. It feels like this bike, in box stock trim, you had to force the thing to make a turn. Of all the bikes thus far, this was the most difficult to ride, to try and ride quick anyway. The suspension’s nice and plush. The brakes work good. The power feels good, if not better than, everything I’ve ridden. It’s more difficult to ride because you have to manhandle the thing. It feels like the ’86, as you are sitting in it. It lost the feel and maneuverability they gained in ’91 by sitting on top. It feels more like a sport tourer, like a road bike, not something you’d want to take to the track. It would be a difficult piece to race. I think you would notice the 25 pounds they removed for 1994 in the acceleration and the handling of it. I’m not sure it doesn’t need more than 25 pounds of a diet, though.” Then the 1993 World Champion joked, “Suzuki obviously focused their efforts more on their two-stroke projects than their four-stroke projects in 1993.” After only four laps Spies came in looking pale and asked if he had ridden the 1993 enough. Spies had a hard time softening his comments for the benefit of McSpadden, saying, “That sucked! Er, um, I mean, it’s not as good as the other ones. I wouldn’t race it. You can’t turn it. It’s heavy, and it just doesn’t want to turn. I have no clue what changes Suzuki made, but you have to pull it down. If you get back up in the seat, it stands back up. It might be able to wheelie, though. I wouldn’t have been happy if I had been riding for Suzuki in 1993. Maybe when the race teams got it, they could make it pretty good. As far as a streetbike, taking it to the racetrack, I don’t think it’s that good of a bike out of the box. It might be an alright streetbike. It’s stretched out pretty good and comfortable, but it’s not the hottest thing on the track. This ranks last. It’s the worst. The ’86 handles better than this. Suzuki must have been paying all of their attention to Schwantz in Europe.”
Suzuki engineers heard the press’ cries and reacted accordingly while bigger plans developed. The $8099 1994 GSXR750SPR-model went on a diet, losing about 25 pounds via reduced frame wall thickness, new magnesium valve and engine covers, lighter brake rotors, hollowed transmission shafts, and machined transmission gears. But the GSXR’s diet didn’t preclude some new goodies. The forks grew from 41 to 43mm but with thinner walls to help the weight problem, the rear tire widened to a 180, the front brakes sprouted six-piston calipers, and the swingarm got a bridge-type brace. The engine tolerances got tighter, squeezing about 5.0 more horsepower, once again just nipping the 100 mark. In 1994, the GSXR 750 faced class competition from the Ducati 888 LTD, Honda’s RC45, the Kawasaki ZX-7, the Kawasaki ZX-7R and Yamaha’s YZF750R in the June 1994 issue of Cycle World. The GSXR was the least expensive, fastest in the quarter-mile at 10.7, tied for last in top speed at 155 mph, second-heaviest, next-to-last in braking distance, next-to-last in roll-on acceleration, third most powerful on the dyno, but next-to-last in Willow Springs lap times. But in the hands of Tom Kipp, the 1994 GSXR750 won the AMA 750cc Supersport title, the model’s fourth crown in seven years. There were no changes but a $400 price increase to $8499 for 1995. In 1993 Sportbike reported, “The original GSXR reversed an earlier cycle of weight growth. It will happen again, and perhaps Suzuki will be the instigator, or perhaps not.”
About that same time, Suzuki engineers were having a meeting that started the program that resulted in the 1996 GSXR750T-model. Marketing gimmick or truth, Suzuki engineers said that they used the size and aerodynamic shape of Kevin Schwantz’s 1993 500cc Grand Prix World Championship-winning RGV500 as a starting point for the design of the 1996 GSXR750. The new model’s twin-spar perimeter frame was twice as stiff and 5.0 pounds lighter than its predecessors! A 55.1-inch wheelbase, 24 degrees of rake, and 3.9 inches of trail were chassis numbers straight off Schwantz’s racebike. Lightweight forks, a braced swingarm, a piggyback-type shock, lighter wheels, lighter brake rotors, and a two-piece removable subframe completed the most race-ready chassis to date. Weight reduction efforts went so far as to reduce the number of fasteners used on the bike by 10 percent, saving over 2.0 pounds. Suzuki engineers claimed that with the weight reduction and horsepower increase, they had their best power-to-weight ratio ever at 3.1 pounds/horsepower. The new GSXR750 weighed 451 pounds fully wet or about the same as the 80-horsepower 1986 GSXR750. The new frame allowed for a conventional engine location, and the utilization of downdraft carburetors.
Suzuki engineers started with a clean sheet here as well. Gone were the cylinder liners and in their place were nickel-silicon-carbide-coated siamesed aluminum cylinders saving weight while reducing cylinder width and depth from front to back. Moving the cam drive to the right side reduced crank bearings from six to five, also reducing engine width. Overall, the new engine was 1.2 inches narrower. The engine’s front-to-back dimensions were reduced by a triangular arrangement of the crank and transmission shafts and a horizontally split, three-layered crankcase that allowed access to the transmission without disturbing the crank. With the new engine forward and the valve angle narrowed, the intake tract was severely straightened. Lift the hinged fuel tank, prop it up on its rod, remove the air box, shine a light down the Suzuki Electronic Enhanced Carburetion-controlled 39mm carburetors, and you could see the valves. Suzuki engineers claimed 127 crankshaft horsepower from the new, oversquare 72x46mm motor. Although readings varied widely from bike to bike, horsepower at the 6.0-inch rear wheel with 190-section tire ranged from 110 to 118 with 110-112 being typical. But some of those 118-horse engines didn’t last long. Either the engine blew or was slightly detuned with a thicker head gasket when Suzuki recalled the GSXR750T for inadequate piston-to-valve clearance. Of course, all the horsepower numbers were recorded without the benefit of the very effective Suzuki Ram Air Direct (SRAD) system.
Everything was wrapped in lightweight, aerodynamic bodywork with a distinctive anti-draft tail section. Suzuki then blew everyone away by offering this incredible new package for only $8999. Yoshimura’s Aaron Yates and Pascal Picotte blew everyone away in AMA 750cc Supersport competition, also. Yates made it five titles in nine years for the GSXR750. What a difference a couple of years can make. In May ’96, Cycle World had an “Ultimate Sportbike Challenge” comparing the new GSXR with Kawasaki’s all-new ZX-7R, Yamaha’s YZF750R, Honda’s CBR900RR, and Ducati’s 916. Once again the GSXR cost the least, but now it also weighed the least, had the fastest top speed, went quickest at the dragstrip, was best on the brakes, second-fastest at Willow Springs by 0.02 second to the Ducati, and third in roll-on acceleration. Kawasaki’s new bike was close to the new GSXR750 in power but weighed 65 pounds more. Due to the rule structure in AMA 750cc Supersport, Muzzy Kawasaki felt that the ZX-7R was so uncompetitive that the team withdrew from the class mid-season. The 1996 GSXR750 made 750cc Production/Superstock/Supersport classes everywhere a Suzuki spec-class from 1996 to present. Cycle World called it , “�the Suzuki GSXR750, the closest thing yet to a street-legal GP bike.” Motorcycle Consumer News wrote, “�open-bike power, middleweight handling and superb attention to detail, it’s really in a league of its own, and the unquestionable winner here.” Racetracks became infested with the new GSXR750.
As a streetbike, the new Suzuki was actually one of the more ergonomically comfortable GSXR models. A lack of midrange power hurt the Suzuki’s street performance slightly, or at least was the only nit to pick. The GSXR became the V-model at $9199 and unchanged for ’97 except for the birth of its little brother, the GSXR600. Jason Pridmore won the AMA 750cc Supersport title for Hyper Cycle that year while Peter Goddard and Doug Polen took the World Endurance Championship including 24-hour wins at Le Mans and Spa. This was the GSXR750’s sixth AMA Supersport and third Endurance World Championship. At the press intro of the 1998 GSXR750 at Road Atlanta, Suzuki’s Press Relations Manager Mark Reese said, “We’re at a point on high performance models where we’ve basically reached a limit with carburetors and emissions requirements.” Suzuki added a fuel injection system featuring the same Mikuni injectors, Denso engine control module (ECM), and sensors as the 1997 TL1000S, with a single injector per cylinder and 46mm throttle bodies. The factory aimed for a 5-horsepower gain and most dynos showed the new power output to be around 115. Other changes included cams with more lift and duration. Exhaust revisions and a flapper valve in the airbox were aimed at improving the midrange. The fuel injection system and associated electronics added weight, but weight savings came from reducing the primary drive gear width by 1mm, the #530 chain to a #525, “narrow waist” crankcase bolts, and individual coil/spark plug caps. Weight still grew by 8.0 pounds, to about 459. Brake rotors grew in thickness to help racers who had to replace the thinner ones nearly every race weekend. The rear shock’s link mount was strengthened. A non-adjustable steering damper was added.
The 1998 bike also got revised spring rates and damping. The rear shock got a further improvement thanks to knowledge borrowed, once again, from Suzuki’s RM. A metering rod expanded and progressively restricted a damping orifice to maintain damping characteristics as the shock heated and the oil thinned. The biggest complaint about the new GSXR750 concerned the abrupt off-on throttle response of the fuel injection system. Aftermarket companies provided command modules that could be plugged in to alter the computer’s fuel and ignition mapping to tune out the off-on throttle problem and to tune in a new exhaust system. Richard Alexander won the 1998 AMA 750cc Supersport title in the last race of the season over Steve Rapp. The GSXR750 got bold new graphics for 1999 and its eighth AMA 750cc Supersport Championship in 12 years from Chaparral’s Tom Kipp. Since the 1996-1999 GSXR750 had no true 750cc peers, magazines started comparing the bike against bigger machines. Cycle World pitted the 1998 GSXR750 versus the Kawasaki ZX-9R, the Honda CBR900RR, and Yamaha’s YZF-R1 in April, 1998. CW reported, “�are far as modern sportbikes are concerned, the trend began in 1985 with the revolutionary aluminum-framed Suzuki GSXR750,” and “All of a sudden, the GSXR feels kinda uncomfortable on the street, kinda heavy-handling on the racetrack and seriously hurting for midrange power.” From the same test, Mark Cernicky commented, “�the fuel injection on the new bike is terrible. It surges at steady rpm, and has an on/off feeling exiting slow corners that makes you feel jerky even when you’re being as smooth as possible.” Nick Ienatsch added, “I don’t like the steering damper’s effect on slow-speed handling.”
The GSXR750 still was quicker and faster than the CBR900RR while being within 0.3-second and 5.0 mph of the other bikes and cost about $800 less. For our test we had arranged both a 1996 and a 1999. Unfortunately, our 1996 didn’t make it. Since the 1996 through 1999 are nearly identical chassis-wise, we just jumped to our 1999 brought by Scott Crawford. You would think a man like Crawford, who qualified fifth-fastest in the 1999 600cc Suzuki Cup Finals, would have a heavily modified street ride but just the opposite is true. Crawford got the bike we tested from a friend who needed money bad, for just $900. Crawford picked the crashed bike up off the ground, replaced the destroyed stock canister with an aftermarket slip-on, spooned on some Dunlop D207 GP tires and started riding it to work. After riding the 1999 immediately after the 1993, Schwantz said, “It’s night and day! Just talking to some of the guys around here, I think Suzuki concentrated on what a streetbike (comfort, cush, plushness) needed to be in ’93. Because it definitely doesn’t work around the racetrack. Of course it’s stock, and I’m sure you could make some adjustments, stiffen everything up a little bit, put a bit more ride height in the rear, and maybe make the thing handle better. It takes an effort. You’ve got to take the thing into a corner, and then you’ve got to hold it down. Not a lot of fun to ride around a tough, bumpy, tight racetrack like Oak Hill. The ’99 is a night-and-day difference. It does everything really good. It turns in. It stops. It finishes the corners. Even some of the early production stuff, the ’86 and ’88, didn’t have the power to finish the corner. The ’99 does everything well.” Spies said, “The bike has a lot of power. I was surprised. (Crawford) says there’s not much done to it, but it runs real good. I think this overall deal is a really good package. It handles good, and it’s got plenty of power. It handles better than any stock suspension bike that I’ve been on. It wasn’t dancing and bouncing around. It was pretty planted for it being bone stock. This is pretty much identical to my bike except it has 150 more cc, but it turns in and handles a lot like the ’88. The ’86 you sat way down low in it. This one you’re up high like a racebike.”
Then we asked Spies to re-think his early response that the ’88 and ’91 were pretty close to his modern racebikes, and Spies said, “Yeah, they’re still pretty close except for the power and the way they look and all.” Crawford, who knows Spies from CMRA racing, heard this and joked, “I think Ben had too long of a lunch break. I had a bunch of those old ones, and they’re nothing compared to the new ones. The ’96 had it all over the old ones, and the fuel injection just makes it that much better.” During the owners’ riding sessions, Crawford looked so fast that Schwantz asked for a stopwatch to put on him. We also asked Schwantz about the resemblance (Suzuki claimed) between his RGV500 and the ’96-and-up models. Schwantz said, “I see it to a certain extent. It feels like my bike was a lot more nimble than these bikes obviously. The ’99 wants to do things that the Grand Prix bike did in ’93 when we won the World Championship. It doesn’t feel like it does anything really wrong. It stops, it turns, it lets you get the thing on its side, it lets you get back if you miss the apex of some corners, in all it’s a pretty forgiving motorcycle similar to the GP bike. And it’s real adjustable, allowing it to work at a lot of different racetracks. The ’99 gives you a real confident feel. It’s real balanced and a lot of fun to ride.” Some may say that the GSXR750 has no competition and ask, “Why bother to change it?” Although the 1996-1999 GSXR750s have cornered the market on most racetracks and in 750cc sales numbers, the fact is that Suzuki built this machine for the same purpose today as they did in 1986-to win National and World Superbike races. In those categories, the GSXR750 has a lot of competition especially from all of the V-Twins. Even though Pier Francesco Chili put the GSXR750 on top of the box a few times in 1999 World Superbike competition and Mladin won the 1999 U.S. Superbike Championship, for 2000 Suzuki engineers again remade the GSXR750 while keeping the price at $9399. The Suzuki men shaved every gram of weight off of the new model while making it smaller, better handling, and more powerful for street riders and racers. Although it looks about the same, the frame of the 2000 model is all-new. The 4.0-pound-lighter frame is smaller to carry the 4mm-shorter (top-to-bottom), 8mm-narrower, 15mm-shorter (front-to-rear), and 11-pounds lighter engine. The swingarm lost 800 grams while being lengthened. The swingarm grew 20mm while increasing the wheelbase only 15mm thanks to the shorter engine. To keep the quick steering, the rear wheel was reduced to 5.50-inches, carrying a 180 tire while the front end geometry stayed the same. Front weight bias has gone from 50/50 to 51.4 percent front/ 48.6 percent rear. The front brake rotors are lighter with four-piston calipers (with aluminum pistons) replacing the six-piston calipers used since 1994. Lighter wheels, bodywork, shock, and forks complete a chassis that is 18 pounds lighter than the 1999 model’s.
made in the image of 500cc racebikes.
The 2000 GSXR750, at 428 pounds fully fueled, now weighs less than the original 1986 model. Weight was removed from the engine by lightening the rods, crank, valve springs, cams, alternator, head casting, and wrist pins. Now the Suzuki’s cylinder is cast as one piece with the upper crankcases, saving weight and adding strength. Suzuki engineers also eliminated external oil lines, routing the oil through passageways cast inside the cases and head. But the biggest improvement to the engine, and the entire bike for that matter, comes in the form of the revised fuel injection system. Anyone riding the two bikes back-to-back can feel the difference. Suzuki engineer Kunio Arase developed a fuel injection system that works like a digital CV carburetor, using a second set of butterfly valves controlled by a more-powerful ECU. While the rider opens the primary throttle butterfly valves with the twist grip, the ECU opens the secondary throttle primary valves progressively to maintain intake velocity. The result is the elimination of the off/on throttle abruptness, exponentially increased midrange, and a measured 126.6 rear-wheel horsepower on a Dynojet Model 200 dyno, in the hands of Roadracing World.
in every external dimension when compared to the original GSXR750 engine.
It also makes a lot more horsepower.
Normally racers get access to their bikes before they are in showrooms to make the early season races. Word is that Suzuki purposely prevented this in 2000 because the new bike, out of the box, is better than most developed 1999 racebikes and would therefore give an advantage. Schwantz said that he could take a stock 2000 GSXR750 with all of the street gear (including lights, turn signals, mirrors and standard tires) and beat his pole position time from the 1988 Daytona 200, which was 1:55.1 running the slower, short chicane. Schwantz had ridden a 2000 GSXR750 a few times before arriving at Oak Hill but was still impressed after lapping Oak Hil. ” It’s amazing what a good production bike can do as far as getting that enthusiasm, going out and riding, and having fun,” Schwantz said. “I just get a little more used to it every lap. Of all of the riding we’ve done today from the ’86 to the ’88, the ’91, the ’93, the ’99, I think they’ve picked up all of the good traits, as little as they may be, of all of the GSXRs and got them maybe all in one package. It’s a really fun bike to ride. Also consider the fact that I haven’t been on a production bike in�forever. It’s a fun bike to even ride slow. Then you can progress to getting faster and faster on it. It stayed as much fun to ride, and it still did everything good from slow to, well, not top-level competition, but respectable times for an old man anyway. The suspension works great. If I were gonna race it regularly, I’d probably make an adjustment here and there. Straight out of the box, it’s still a remarkable bike to ride.”
Kevin Schwantz watches from the seat of the 2000 GSXR750.
I must say that, (and I think that I speak for everyone in attendance at Oak Hill that day because they all stopped what they were doing to come watch with many cameras rolling), that it was worth everything it took to make this test happen just to watch Schwantz ride hard laps on the new GSXR750. We knew he was riding hard because he ran off the track twice. Schwantz explained, “Just going in, getting in a little hot, and going to use a little rear brake, just set the back end off hopping. Maybe backing it in was the answer to the problem. Both times it gave a good kick, and I had to get off of the front brake to get the thing back in line. It caused me to go in the grass a couple of different times. Hey, you’ll never find where the limit is unless you keep trying harder and harder.” Roadracing World was also doing a big-bike comparison with Michael Martin, Mark Junge and Grant Lopez on race tires that same day at Oak Hill. Schwantz’s fastest lap on the 2000 GSXR on street tires without one single adjustment was only beat by two of those men, and one of those only beat the time on one of his laps. After riding what will soon be his new racebike, Spies said, “The new bike is unbelievable! It handles so good. It only had street tires on it today, but it worked well enough that you could get on the gas and see how it did. It has so much power for a production bike. Suzuki really nailed it on this one. (Comparing the ’99 to the ’00) The 2000 definitely has more power, but you can’t even compare the handling. The 2000’s that good. You have to be careful getting on the throttle because it’s real jumpy. Other than that, it’s a perfect bike. The brakes are awesome on it. Compared to the 1986, it has changed a lot! The biggest differences are probably the carburetion, the handling, and the suspension. Of course, they changed the frame and geometry and all, but that’s scientific stuff. But the ’86 was a good bike.” Spies then borrowed his mom’s cell phone to call Valvoline EMGO Suzuki teammate John Hopkins, to tell him about the new bike. This article took months of preparation and too many hours of research to count. Through the effort, I learned a lot about the incredible evolution of the Suzuki GSXR750 model line. I hope that I have been able to do justice to a truly historic motorcycle. I also hope that in 15 years we can do it all over again with Schwantz, Spies, the next rising star, and the 2015 GSXR750. How much better will that Suzuki be?
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