Corona Suzuki GSX-R1000 | Review

Superbike Test

No neutral observer of the titanic on-track battles and off-track spats between Max Biaggi and Valentino Rossi can fail to regard Biaggi as a genuine superstar—a man who has displayed skill and courage in garnering 42 Grand Prix race victories, four successive 250cc GP world titles, and three runner-up slots in the MotoGP premier class series. Having switched this year to World Superbike with Team Alstare Corona Suzuki, Biaggi promptly won his very first race on the GSX-R1000 K7.

Riding the Biaggi bike at a private test day at Germany's EuroSpeedway Lausitz gave me a hands-on look at the factory Suzuki that is an evolution of the bike on which Troy Corser won the World Superbike crown in 2005. Redesigned for 2007, the K7 employs an all-new frame while retaining the same longest stroke motor of any four-cylinder 1000cc sportbike. "The engine is not so different than before," says Alstare technical guru Bruno Bailly. "Just the cylinder head is new. But, after modifying the combustion chambers, and polishing and flowing it to the same specifications as last year, we were disappointed to find it was five horsepower down on the K6! That's because both riders wanted a bike that was easier to ride, so we'd left in the counterbalancer which made the engine vibrate less." (Click image to enlarge)

Biaggi won in Qatar with an engine that was deliberately down on power compared to last year's bike, which produced 210 hp at the gearbox! "But then, as the other teams improved, especially the new Yamaha, he realized he needed to have that extra top-end performance," says Bailly. "So here at Lausitz, we've removed the balance shaft again, and now he's happy!" (Click image to enlarge)

This would explain the surprising drop in top speed at Monza this year, where both Corona Suzukis were trapped at "only" 194 mph, whereas a year ago Corser was timed at an even 200 mph on a bike that was minus its counterbalancer. I did not notice any undue vibration even at high revs, though it seemed to pick up revs quickly despite the longer stroke, a fact Bailly put down to the reduced friction of Alstare's own new forged two-ring pistons, rather than the three-ring factory ones used so far this year. However, top speed wasn't an issue at this twisty track, where Biaggi uses just the bottom five gears of the works transmission, with a choice of four different ratios for each gear matched to the factory slipper clutch that replaces the STM unit used at the start of the year.

I had to get comfortable on a bike with a quite different riding position from the balanced, spacious stance of Troy Corser's K6 of 2006. Corser's bike was also lower at the rear, making the rear tire work harder for extra grip. Biaggi prefers a more close-coupled tail-up stance, a legacy of his 250 days. As I expected, his 2007 Suzuki was much taller at the rear and lower at the front, with a thick seat squab pushing my body weight forward and wedging me firmly in place to deliver a 54/46 forward weight bias. Moving back and forth in the seat was not an option, until I stopped and got Biaggi's race engineer to take the squab off.
That got me comfy on the Suzuki, with handlebars that are also more steeply dropped than a year ago. The digital dash between them has a row of green lights on the top, surmounted by a bright red light that flashes at around 13,800 rpm telling you to hit another gear wide open on the powershifter before the 14,300 rpm rev limiter cuts in. Biaggi is one of the few top riders using a street-pattern gearshift and this takes quite a bit of getting used to; sometimes you have to short-shift, because you can't get your toe under the lever to shift up a gear when cranked hard over to the left. At least the GSX-R1000 motor is plenty torquey enough to let you do that.

On the left handlebar is a switch accessing one of the two different engine management maps. There is an up/down button providing five different settings within each of those maps for both traction control and engine braking, varying the idle speed while backshifting. On the right clip-on is a headlamp flasher switch acting as the pit lane speed limiter, it is next to the button for the electric starter which Alstare still retains on the bike. It is evident Biaggi finds the tacho readout on the Marelli dash just as hard to decipher as I did, as the team has stuck small white numbers at the top of the screen so he can check the revs at a glance.

The different chassis setup and riding stance paid off in the many tight turns at Lausitz, where the Suzuki felt lighter-steering and easier to change direction than last year's Corser bike—and that is in spite of the new K7 chassis seemingly being wider. The frame is composed of six different cast aluminum sections, welded together to create an altered degree of controlled response compared to the K6. The GP-derived setup really works at letting you flick the Suzuki more easily than last year's heavier-steering bike. It felt poised and controlled in the way it changed direction so quickly, but without seeming to want to tip into the apex of the turn, and without sacrificing stability on the faster fourth gear sweepers later in the infield. There, the track was surprisingly bumpy, with a washboard surface that tested the Showa suspension. Riding a Superstock GSX-R1000 earlier in the day, I experienced serious chatter over the ripples from the stock forks that was absent on the Superbike.

The Biaggi Suzuki is outstanding on the brakes, the Showa forks absorbing those bumps even under the extreme weight transfer imposed by the four-piston Brembo radial stoppers that combined with the factory slipper clutch and Marelli ECU's variable idle speed program—as honed to perfection on Rossi's Yamaha—to deliver very effective braking, with zero instability and no rear wheel chatter. However, there's also very little sensation of any engine braking. Biaggi has it set up so that you almost feel you're riding a two-stroke, even when you back down the gears using a lot of revs on the overrun.

The foward weight bias and low bars on the Biaggi Suzuki pay dividends when changing direction.

It is a bit like the early YZR-M1 Yamaha that Biaggi rode to occasional GP victory, and on that bike the flawed computer-controlled transition on the exit of the turn from near-zero to full-on engine response was often a recipe for a highside. Not so on this Suzuki, where four years of experience has allowed Marelli to refine the software so that the transition is now seamless. The way the Biaggi bike hooked up and rocketed out of the last second gear turn and down the front straight—with literally awe-inspiring warp-factor acceleration—was extremely impressive.

Swapping to a Magneti Marelli ECU after the start of the season wasn't an ideal scenario, but one actively furthered by Suzuki. "We switched for several reasons," says Bailly. "We understand the system easier, and Marelli's response for new software is very fast –whereas Mitsubishi was much less responsive. The Marelli also gives us more choice in our engine setup strategy—it's more versatile. It would have been better to have made the change over the winter, rather than mid-season, but after this Lausitz test I believe we have good parameters for the rest of the year." Clearly, Biaggi's Brno victory shows that was not a case of excessive optimism!

The result is a smoother and more effective delivery of the Suzuki's horsepower from what is effectively the same engine as a year ago. There's still a brusque pickup from a closed throttle in second gear—it likes to push the front wheel exiting a turn if you are not ready—but in every other way, the power delivery feels more refined and controllable than the old bike. That improved feel comes despite the removal of balance shaft and clutch flywheel, and the fitting two-ring forged pistons delivering a steep 15.2:1 compression.

Sleek and at the ready, the Corona Suzuki GSX-R1000 is a winner at the highest level of Superbike racing. (Click image to enlarge)

The lower of the dual butterflies fitted to the 44mm Keihin throttle bodies has been removed to produce a cleaner intake flow, at the expense of a sharper initial response. The remaining butterfly combines with the slipper clutch to help prevent rear wheel chatter under engine braking by varying the idle speed under deceleration via an electric stepper motor, according to the gear selected. The stock throttle bodies feature the same twin intake trumpets per cylinder—one short and one long. They are claimed to soften the torque curve, though Alstare is still experimenting with different lengths in order to fine tune the power delivery. Twin injectors are fitted to each throttle body, both positioned above the remaining butterfly, with the upper injector at a steeper angle than the lower, flatter one.

This year's Suzuki engine is also torquier—whether for mechanical or electronic reasons, I can't say—and its flexible nature let me use third gear for long sections of the Lausitz infield, building very strongly from 8,500 to 11,500 rpm. There is a huge hit of grunt from just under 12,000 revs up to the point the shifter light flashes just 500 revs below the 14,300 rpm rev limiter. This is higher than either the Kawasaki or Ten Kate Honda, in spite of the Suzuki having the longest stroke in the Superbike class. But from the 12-grand mark to the moment the shifter light flashes in your face 3800 revs later, there is a great surge of usable power from the Suzuki, delivered with addictive force as you catapult out of turns down to the next corner.

Once I got used to the street-pattern powershifter, I found it even faster shifting and more precise than a year ago, when the six-dog pinions were introduced to replace the slightly heavier-shifting three-dog setup of before. This delivers that warp-factor, wheel-free acceleration that is so impressive, and would account for Suzuki's impressive wins at Qatar and Brno—tracks with many sweeping turns followed by short straights. Marelli's anti-wheelie ability has already proven to be extremely effective on other bikes, including Suzuki's GSV-R MotoGP contender. There was a big contrast between the Biaggi Suzuki and last year's Mitsubishi-equipped bike, which was much more wheelie prone.

I did not care for the rather vague feeling I had from the back end of the '07 Suzuki. There did not seem to be the same feedback from the rear tire I received on previous GSX-R1000 Superbikes. The front seemed fine—as responsive and planted as ever, on a par with the WP forks on the Toseland Honda. I had a strange semi-detachment from the rear end, and I certainly didn't feel that legendary connection between throttle and wheel exiting a tight turn. Perhaps 20 laps is not enough track time to get to understand a bike that had its character so totally changed by its new rider. But, I just did not feel immediately confident on the Suzuki in the same way as I had on the Toseland Honda or Bayliss Ducati.

The GSX-R1000 may look as if it has two exhausts, but only the left exhaust is live, due to a quirk in World Superbike rules. (Click image to enlarge)

"You're in good company!" said Biaggi's race engineer Giacomo Guidotti when I stopped to try some new suspension settings. "Suzuki changed the chassis for 2007, and this one has different flex, and the rear suspension is an all-new Pro-Link design, which means you can alter the link, ride height and swingarm pivot. But the riders don't like it as much as last year's bike, especially at the rear where they can't get the same feeling as the old one. That's in spite of trying many different links, and this is our fourth different swingarm. It's a very complicated bike to set up, especially for someone as sensitive as Max, who will spot if a tire has turned even just 10mm on the rim, as often happens."

"We know what Yoshimura have done in the AMA series to correct the handling issue," asserts Bruno Bailly. "They use a mixture of 2006 and 2007 parts, and modify the anchor points for the shock—all things we're not allowed to do under SBK rules." However, a close reading of the rulebook has allowed the Belgian Suzuki team to pull one neat stunt, though. Unlike the previous K6 version's single-can pipe, this year's K7 Suzuki has a twin-silencer exhaust system. Because SBK rules demand an identical silhouette to stock, Alstare Corona adapted its 4-1 Arrow system into what looks like a 4-1-2 format; except, the right-hand silencer is a dummy. Biaggi's bike actually exhales only through one silencer.

Though handling issues caused by the new rear suspension may yet prove insurmountable without the ability to mix-and-match parts from older models as Alstare believes the Yoshimura team has done in the USA, the Suzuki's wonderful engine is the key to an otherwise outstanding motorcycle. It has an even better power delivery than before, and the adoption of Marelli engine management will get the most out of the existing motor. I can not help feeling that Suzuki is ultimately going to have to go for a shorter-stroke version that delivers more revs and better breathing to successfully match the increasingly competitive engine performance of the new same-format Yamaha. Or, just maybe, to take a lead from Honda's and Aprilia's future models, and go the V4 route, perhaps by adapting their now successful GSV-R concept to the one-liter Superbike class. Now, there's a thought!


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