From the outside the GSX-R750 looks the exact same as its little sibling, the 600, but the changes became apparent once the rubber hit the track at Phillip Island.
Since 1985, the GSX-R750 has what some consider the perfect balance between the handling and braking package of a 600cc supersport bike, without the fear and ballistic speeds of a 1000cc machine. It could be the best real world compromise for track days and fast street riding, and this was the gist of the PR spin that was being presented at Philip Island, especially when the bike is almost identical to the GSX-R600 except for some color changes and larger engine internals.
It is an interesting move for Suzuki to be so committed to this class, with the other manufacturers abandoning sportbikes of this capacity. But enough 750s must be rolling out of dealer showrooms because it is back for 2006, and back with a bang.
In regards to the chassis, suspension, brakes, bodywork and wheels, the bike is absolutely identical to the GSX-R600. So, like its smaller sibling, it is radical change from its previous model year and not just a simple make-over. Where it differs from the 600 is inside the engine, and this year's model is making more horsepower, although Suzuki didn't provide exact numbers.
Inside the new compact engine, lighter pistons run in a larger bore. Capacity remains the same, but the compression ratio is increased from 12.3:1 to 12.5:1 and the rev ceiling is raised to 15,000. As with the GSX-R600, the piston skirts are shorter and the rings treated to a chrome-nitride coating for less friction. The rods are shot-peened for extra strength and a new secondary balancer shaft has been added in front of the crank. Valve angles are also reduced, while the intake and exhaust ports are shortened. The valves are still titanium, but the exhaust valves are now smaller and their cam lobes gets more lift.
Fuel injection is the same as the Six with the new dual injectors, as is the whole exhaust process, with both bikes meeting stringent Euro 3 emissions standards thanks to catalytic converters and oxygen sensors. Like its smaller sibling, a slipper clutch is used this year, and the bikes' gearing reworked a little for better acceleration on the racetrack. One thing that hasn't changed on the '06 is the weight, although with more horsepower (now up to a claimed 148 at 13,200 rpm) and an improved handling package, our ride was guaranteed to be more exiting than ever. And, out under the Australian sun on the high-speed Phillip Island racetrack, there were certainly no disappointments.
The 750 owns a beefier powerplant than the 600 and only a 4-lb weight increase, so riding the 750 around the Phillip Island circuit required a different approach.
With an additional 25 horsepower over the six-hundred but only a four-pound increase in weight, the GSX-R750 was way faster everywhere on the circuit. It obviously felt very similar physically, but once the clutch was dropped the similarities ended. The track immediately became a different place, and my whole ride strategy quickly had to change.
Exiting the Melbourne Loop on the smaller machine was a throttle-pinned affair, holding the bike wide open through Turn 3 on the run up to Honda Corner. On the 750, my exit speeds out of Melbourne I would imagine were identical, but Turn 3 was arriving much quicker and at higher speed. During the early sessions, this necessitated rolling off the throttle slightly and a lot more physical effort to keep the bike from running to the outside of the track.
Finally finding the minerals to hold the throttle on was an enlightening experience. With most of the extra weight coming inside the engine as rotating mass, getting the bike leaned over was a lot harder and staying on the solid stuff a little more in doubt as I ran toward the edge of the track. This just made the approach to Honda more hectic as I was on a different line and it was coming up at a greater rate of speed.
No problems from the brakes or suspension, and banging down the gears with impunity, knowing the slipper clutch would save my sorry arse if I made one too many, wasn't a problem other than the increased physical effort to keep the Bayly blubber off the triple clamp. Of course, even a 250cc Grand Prix bike is going to get hard to turn if you go fast enough, but combining the extra speed and engine weight made the high-speed Phillip Island a noticeably more challenging circuit.
To more precisely describe the difference of feeling, it was as if the 600 were a scalpel and the 750 a sharp blade. On the smaller displacement machine I felt as though my laps were closer to being inch perfect, finding the best lines and riding as neatly and cleanly as I have in a while. On the 750 I was still fast, for me, but it was not as pretty, with a few more erratic lines and some interesting moments when the rear wheel would spin up out of Turn 10. If we had more time, I would have needed to make some changes to the rear end of the 750 also, as it was a set up a little too soft, but with only three sessions I didn't get to that speed point until the end of the day.
The 750's extra power meant the corners arrived a little quicker than on the 600, necessitating a let off on the throttle and forcing different lines. The 750 was also more difficult to lean over than its smaller-displacement Gixxer kin, thanks to the extra speed it generates and the greater mass of reciprocating internal parts.
Shifting up out of Turn 11 ended the rear-wheel spin as I got my head down and accelerated for the extremely fast Turn 12 that leads back onto the long front straight. Rolling off a touch before blitzing into the corner, the bike would hold a good line through here and I would let it run wide out to the edge of the rumble strip allowing the bike get as up right as possible before twisting the throttle back to maximum as early as possible. Rolling off at the other end of the straight approaching 170 mph, the stability under braking was perfect, and the bike was rock solid taking the turn somewhere around 120 mph, with no protest from the tires.
Talking with one of my peers, we worked out my fast laps were probably about 7 seconds off Kevin Schwantz's pace during a demo session (he probably wasn't even trying), so I guess the fact I never get close to the bike's full potential just got well rubbed in once more, although it is a useful piece of information. In a regular trackday situation, the GSX-R750 is going to be a formidable weapon, and with so much more ability in reserve one that will be able to continually challenge new owners to improve.
At the end of the day, our trip to Philip Island was not a comparison test or a venue to pick a winner between the two Suzukis on test. It did however make it very clear that as fast as the 750 was, and as complete of a package, I think if I was presented with the choice, I would take the 600 because I felt a more in control. Faster riders I am sure would opt the other way, but one thing is for sure, neither choice would bring any disappointment.
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