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Switching Sides
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Corona Suzuki GSX-R1000 Racer
Alan Cathcart
10/01/2007
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Photography By Kel Edge
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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.
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