Street-legal Superbikes Go At It On The Road
Although 600cc supersport machines continue to be the sales leader among sporting streetbikes, 2004 is undoubtedly the year of the Literbikes. Three exciting fresh-sheet designs have emerged this year to rival the class overlord Suzuki GSX-R1000.
But lest you imagine yourself ready for these Superbikes, we’d like to remind you that the least powerful in this musclebound quartet produces 148 horsepower at the rear wheel. This kind of power undoubtedly makes them fun to ride, but it’s serious fun. As in: “Don’t lose focus with me, twerp, or you’ll be showing your insurance card to hospital staff before you can even remember what my redline is!”
How serious? Consider the new AMA Superstock class for these Literbikes. At Daytona earlier this month, Ben Spies rode his lightly modded GSX-R1000 to a qualifying time quicker than the 2003 Superbike pole, set by Ben Bostrom on a full-works Honda RC51!
So, for those of you who believe this class of bikes is pure overkill for the street, we’d have to agree to a certain extent. But for outer-limits riders the kind of people who might like to juggle chain saws as a hobby nothing will get adrenaline coursing through veins like this 600-horsepower group.
Historians will recall that it was Honda that first featured a big motor in a middleweight-size chassis when it unveiled the CBR900RR in 1992. The stumpy little bike was a smash, and it took until 1998 for a worthy rival to enter the scene when Yamaha released its sexy and potent YZF-R1. The One remained the top dog in the class until 2001 when Suzuki introduced its omnipotent Gixxer Thou. Updated in 2003 with an even burlier motor and radial-mount front brakes, the GSX-R set a new benchmark in power-to-weight ratios.
The acknowledged class leader in anything always becomes a target, and one that your rivals know exactly how high to shoot in order to clear the established bar.
The Kawasaki ZX-10R and Yamaha R1 make up two-thirds of the fresh new players in the hotted-up literbike segment ruled mercilessly by Suzuki’s stout GSX-R1000.
A glance through the spec charts of this gang reveals many similarities. Rake angles range just 0.5 degrees; trail numbers just 11mm from most to least. Each bike has a 43mm inverted fork and radial-mount front brakes. The older GSX-R is the longest and tallest, but only by 0.9 inch and 1.6 inches, respectively, from the smallest of its rivals. The Gixxer’s wheelbase, at 55.5 inches, is nearly identical to the CBR1000RR but a full inch longer than the stubby ZX-10R.
Even thought a bull’s-eye is clearly painted on the Gixxer, Suzuki has proven to be incredibly adept at extracting the maximum out of its GSX-R series. The competition is hard-pressed to achieve similar performance numbers, and we’re not just throwing Suzi a juicy bone here. On the dyno, the Gixxer’s motor bested all but one of its new rivals when considering production of both horsepower and torque. On the scales, the Suzuki proves to be the second lightest of this steroid-injected group.
But all must bow down to a new king of power-to-weight ratios, Kawasaki’s ZX-10R. Having the most horsepower and torque obviously helps the equation, but having the lightest weight of the four contenders absolutely seals the deal. To gain further perspective, consider that the 10R boasts a whopping 50 additional horsepower over its ZX-6R little brother while weighing in just 14 pounds heavier than the 636cc bike.
Easy Being Green (or black)
We knew the ZX was something special after editorial director Ken Hutchison came back from its press introduction at Homestead Speedway in Florida, raving about huge power in a middleweight package. Indeed, 156 rear-wheel horsepower (on the White Brothers Racing Dynojet dynamometer) and a 403-lb tank-empty weight will elicit that kind of response.
As even the dimmest of wits could realize, the ZX-10 is supernaturally quick to accelerate. Before experiencing the full-throttle warp drive that the ZX can deliver, we suggest a few weeks in the gym, as speed piles on in 10-mph gulps that make a rider feel like he’s just been thrust into a to-the-death tug-of-war with The Rock. Its get-go from a dead stop is slightly muted by an overly tall first gear, but once it hits 7000 rpm this thing is a missile until it signs off 6000 rpm later. We were never exactly sure what the old Kawi advertising tagline “Kawabunga” meant; we’re getting with the program now.
The ZX was the first of this group to enjoy the splendor of MCUSA’s SoCal garage, and we quickly were taken with our metallic-black beauty. Its rawness is immediately apparent, whether speaking of its impressively unglamorous and business-like appearance or its deep-chested baritone exhaust that will never be mistaken for a puny 600. While bikes such as a Ducati 999 or even the R1 entice a rider to go fast, the ZX demands it no sissies allowed!
Over the years, much ink has been used to tout that Bike X is an open-class weapon in a middleweight chassis. In 2004, no one pulls off this dichotomous distinction better than the Kawasaki. The reach to the bars is short, the fairing is the skinniest of this group, and tossing the ZX back and forth between the legs makes one imagine there might be helium in the tires. While your knees are rubbing against the purposeful-looking, recessed-top fuel tank, you’ll notice a very narrow midsection. Kawasaki’s use of an up-and-over twin-spar frame layout has allowed engineers to make the frame only as wide as the engine below, resulting in a diminutive feeling for the rider.
While waiting for our CBR and GSX-R to arrive, we took the ZX and R1 to the backroad playgrounds of Southern California as a sort of undercard for the main event. As I had attended the R1 press ride and “Starsky” Hutchison went to the ZX intro, we were anxious to test what the other had raved about and to see who was more correct about riding the bitchinest bike on the road.
“No matter how hard I tried, I could not get the bike to unsettle in the curvy stuff,” said Hutchison of the R1 after his ride. “Side-to-side transitions, rough pavement, dirty roads none of it mattered to this race-bred piece of rolling art.”
While Starsky was busy writing Yamaha ad copy, I was reveling in the greatness of the ZX. With the shortest reach to the bars, the tightest wheelbase and the least weight, the ripped Kawasaki has the physique of a black-belted martial artist. If the other bikes feel like a 600, then the ZX must be like a 400. In the corners, the closer-coupled riding position made it easy to crawl forward over the tank to get more weight over the front end, either for greater stick at the apex or for helping keep down the wheelies that inevitably accompany a charge on the way out. While the R1 is slim down the middle, it’s actually a bit wider overall than the ZX and a bit more rangy.
With the least mass and the most horsepower and torque, a ZX rider is sitting astride a rocket ready for its fuse to be lit. Each of its 156 ponies carries less than 2.6 pounds! Its excellent cable clutch makes modulating that power a cinch, which is a real blessing on a bike with a 100-mph first gear. Whether dissecting Latigo Canyon in Malibu or climbing Palomar Mountain in northern San Diego county, the ZX can do it all in a single gear. And pull mondo wheelies on the way out of each corner. Quicker steering than the R1, the ZX even shows good stability with a rock-solid feeling despite being the only one in the group without a steering damper. We heard coffee-house bike experts tell us they’ve heard the Kaw tankslaps like the Tazmanian Devil, but any headshake we ever encountered was short and not distressing. We might feel different on a racetrack.
What the ZX lacks in a steering stabilizer it makes up for with an even better and more unique feature. Its slipper clutch makes backshifting no more complicated than on a 2-stroker, letting the rear wheel continue to keep spinning even when banging downshifts from hairball rpm.
Unlike the exhibitionist R1, the 10R in its black guise proved to be the stealth bike. It hardly stands out in a crowded parking lot, and the fact that it’s difficult to appreciate the value of a slipper clutch when parked takes nothing away from its pilot. So, while the R1 rider is being swarmed by moto geeks asking about how fast it goes and if that cool underseat exhaust makes the seat hot (it stops just shy of “hot”), the Kawi rider has a clear path back out to the twisties. Results with the green or orange ZXs may vary.
The R1 makes its case with Ducati-like stability and hellacious powerband that is accompanied by a soundtrack so sweet you’d think you were in George Lucas’ living room with THX surround sound. At 7000 rpm, it’s surging like a pit bull straining against its leash, with a loud intake resonance growling perhaps a bit too ferociously, and it becomes an otherworldly wail as the tach races toward 14K. And the more miles we put on, the more its exhaust baffling was blowing out, making it sound even nastier, especially as it burbled on the overrun.
The Yamaha comes a close second to the ZX in 2004’s Tallest Low Gear award, but the extra muscle in the Kawi helps overcome the slight difference. Our R1 was also saddled with inconsistent response from its engine, having holes in its powerband at both 3000 and 7000 rpm. From the saddle you can feel the bog below 4000 rpm, and holding steady throttle around 6500 rpm is difficult because of a slight surging condition.