Compared to last year's model, the '06 600 has smoother low-end throttle response that lets you crack open the throttle sooner exiting a corner without worrying about unsettling the chassis. Though the meat of the power doesn't come until beyond 8000 rpm, the engine runs cleanly at lower revs, letting you short-shift and pull a taller gear through a corner to reduce wheelspin-especially useful when the tires are worn near the end of a race or track day. That proved useful on the short chute between the Honda Hairpin and Siberia, and between the tight downhill MG corner and the long uphill Turns 11/12 that end a lap at Phillip Island. Speaking of gears, both the 600 and 750 have a digital gear indicator this year, like the 1000, which proved especially useful on the smaller bike. They also have a programmable shift light, which would be more useful if it were moved up higher on the dash and not hidden behind the clutch cable. Rocketing down Phillip Island's half-mile-long front straight on the 600, I had to pay close attention to the tach needle to shift at the power peak, which came a tad shy of the 500-rpm-higher, 16,000-rpm redline. The LCD speedo was set in metric mode the first day, and I routinely saw 250 kph (about 155 mph) before braking (slightly) for Turn 1, named for five-time Aussie MotoGP Champion Mick Doohan.
Speaking of braking, both GSX-Rs have 10mm-larger 310mm rotors this year that work with the Tokico radial four-piston calipers and radial master cylinder to provide superb feel and stopping power. Also helping here is the new slipper clutch, which lets you crowd your downshifts impossibly close to corners, and even bang more than one at a time without having to worry about the rear tire chattering when you release the clutch lever. Revised steering geometry with .5 degree more rake and 4mm more trail improve stability while trail-braking, with no adverse effect on turn-in; if anything, the new bike tips in even better than before. Handling is above reproach-light yet stable even at triple-digit speeds, and there's plenty of cornering clearance even with the adjustable footpegs (hallelujah!) set in the standard middle position. Understandably, the fork and shock springs felt a tad soft for my 6-foot, 200-pound frame.
That wasn't an issue the next day, because the 750 boasts upgraded suspension with stiffer springs, both high- and low-speed compression damping adjustments on the piggyback shock reservoir, and a friction-reducing carbonized titanium coating on the fork sliders. I could feel the improvement from the first lap, as the 750 pitched less under braking and squatted less under acceleration, letting me ride much more aggressively. Beyond that, though, the only real difference was engine power-and man, what a difference. With the new engine's longer stroke, you'd expect it to have a lower redline, but it was in fact raised 600 revs to 15,000 rpm.
With 20 more peak horsepower than the 600, the 750 felt loads faster in a straight line, and with the speedo set in American mode the bike flirted with 170 mph on the front straight. But it was the increased midrange power I noticed most. As noted, there are two places at Phillip Island where short-shifting pays dividends, and while you had to get it just right on the 600 or risk bogging the engine, the 750 pulled cleanly through every time. Short-shifting proved especially beneficial during the second session, when the sun came out from behind the clouds, raising track temperatures from 80 to 100 degrees and reducing available traction from the stock Bridgestone BT014s (which have a slightly different construction than the ones on the 600). Chasing transplanted Aussie Paul Carruthers of Cycle News around the racetrack, I experienced a rash of momentum slides before deciding that discretion was the better part of valor and backing off. Carruthers pressed on, and after he nearly tucked the front end in 100-mph Turn 2 and an Aussie journalist fell in the exact same place, the tire technicians opted to lower air pressures from the standard street settings of 34/36 psi to a race-spec 31 psi at both ends, which worked much better.
Between the lower tire pressures, two turns of spring preload and a half-turn of high-speed compression on the shock, the 750 was on rails in the last session, and I just managed to hold off my nemesis-for-the-weekend Fleming-never mind that he started 10 seconds behind me. Unofficially, my best lap time over the two days was a 1:48 and change-"only" 16 seconds off the long-standing World Superbike lap record set by Troy Corser after the circuit was repaved in 1999. Funny, it felt fast
Snail's-pace lap times notwithstanding, at the end of our two days' testing everyone was thinking the same thought: The new GSX-R600 is a nice enough motorcycle, but why would you choose it over the 750, which works better in every appreciable way?
That Schwantz fellow may be onto something...