Suzuki GSXR600 and GSXR750 on Test at Philip Island

In an interesting twist to the usual press launch format, Suzuki chose to unveil two new motorcycles in Australia at the same time. With the new GSXR600 and GSXR750 being so similar, I guess they felt it would be redundant to do two separate launches, especially with the test venue on the other side of the world. Riding the six first, we were allotted three sessions on the world famous Phillip Island race track, with a further three the following day on the 750.

In the ever increasing battle to trim weight, add horsepower, and re-invent styling, without losing sight of the brand’s identity, it is a wild thought that just two years ago I was freezing the family jewels out on the Santa Monica Raceway in Misano, Italy, testing the previous generation GSXR600. A fantastic machine, which gave very little to complain about, here we are getting set to retire it as the newest rendition hits the track.

With the 2006 GSXR600 getting a new chassis, engine and exhaust system, as well as being completely restyled, this is obviously not a makeover either, this is a completely new model. The new engine’s height is 20mm lower and length 54mm shorter, although internally it retains its 67mm bore and 42.5mm stroke: The same as this year’s R6 and CBR600 for a displacement of 599.4cc. The engine is also titled forward, which moves the center of the pivot shaft towards the front of the motorcycle by 67mm, as well as being 16mm narrower, helped in part by a 5m reduction in the distance from the crankshaft to the input shaft.

In total, the engine produces five extra ponies for a total of 129 and it appears these gains come from a number of places. Spinning 500-rpm higher for a red line of 16,100 rpm, newly designed connecting rods hold forged aluminum-alloy pistons, with 0.5 mm shorter piston skirts and an anti-friction surface finish. Further reducing friction inside the cylinder walls, the rings are treated to a chrome-nitride coating to make them smoother and harder. The same titanium valves are still used, but the valve bucket diameter is now larger to work with the increased lift of the camshafts. These are made from new high-strength cast-iron alloy and are hollow for reduced weight.

To increase the GSXR’s cooling capacity a trapezoidal radiator is used, which also reduces frontal area. Developed on Suzuki’s factory race bikes, the radiator’s curve allows it to be 70mm wider at the top while being narrower at the bottom and taller overall. Not surprisingly, it comes with an improved one-piece molded fan. Behind the radiator, the header pipes now run 54 mm closer to the cylinders, and end up running into the new, shorter muffler that lives lower and closer to the bike’s center of gravity. This is apparently to aid mass centralization, and it makes sense to not have a large muffler dangling out in the breeze. To facilitate this tighter fitting exhaust system, the oil pan shape has been changed, as has the shock linkage system.

On the intake side of the equation, the 2006 GSXR 600 boasts Suzuki_s Dual Throttle Valve system (SDTV). Inside each throttle body, two butterfly valves are used, the primary being opened by the rider with the throttle, and the secondary according to an Engine Control Module (ECM) that takes readings from the engine’s rpm, what gear you are in and what the primary valve is doing. This is said to improve low-end throttle response and torque, as well as increasing combustion efficiency. Considering the phenomenal rev ceiling, it is actually remarkable how tractable and useable this engine is at low rpm, fully validating the system.

For ‘06 Suzuki has also moved to twin injectors, over the previous single unit, for greater efficiency. Receiving fuel for the majority of the time from the primary injector, the secondary unit kicks in when the ECM senses heavy loads at high rpm; a situation that improves racetrack performance. Of course there has been upgrades to the ECM also, and along with all the other electronic wizardry it also controls Suzuki’s variable exhaust tuning system (SET) that lives right before the muffler. Monitoring throttle position and engine speed, a servo-controlled butterfly valve opens and closes to increase back pressure at low rpm, and decrease it as the revs rise.

So with the power unit new, fresh, and bristling with technology, including a slipper clutch, it is no surprise that the chassis has been revised also. Firstly, with the shorter engine in place the frame height was able to be reduced 25mm, which allowed the seat to be 15mm lower. It is also shorter by some 15mm, although the overall wheelbase remains the same as a longer swing arm is now used. The rake has actually been relaxed 0.5mm, which results in 4mm extra trail, and presumably this was done with stability in mind. The new swing arm looks a lot more beefy than the previous model, and provides a home for the Showa shock.

This is attached by the new linkage mentioned earlier, and allows the shock to move in a smoother arc during compression. This new shock has received a lot of attention, with a smaller damping piston, smaller rod diameter and a shorter stroke, which reduces its weight by 15% and height by 15mm. What has not changed is the GSXR_s 130mm of wheel travel. Adding to the usual adjustment options, the rear shock also comes with high and low speed compression damping for further fine-tuning. As is normal at press launches, the bikes came set up for us, and other than a couple of heavier riders needing a little pre-load in the rear the settings were spot on for Philip Island.

In the front a Showa 41mm fork is used, compared to the previous 43mm set up. To maintain rigidity with the loss of diameter the wall diameter is thicker and friction has been cut for more precise wheel movement. It still maintains 120 mm of wheel travel and is adjustable for pre-load, compression and rebound damping. This new fork holds a lighter front wheel this year. Appearing externally to be identical, the three spokes are actually thinner for an overall saving off 100 grams of unsprung weight. The tire remains the same at 120/70-17 and comes wrapped with a nice sticky Bridgestone tire, while the rear remains a180/55-17.

For ‘06, the brake diameter change game continues with the rotors growing from 300mm to 310mm, which probably balances out the wheel’s weight loss. These are still grabbed by a pair of radial mount, four-piston Tokico calipers, and the extra disc width is said to give better braking feel. Reaching speeds approaching 160mph on the new 600 lets just say they felt just fine to me when it came time to squeeze the lever. This part of equation is adequately covered, as on last year_s bike, by a radial-piston master cylinder with a six-position adjustable brake lever.

With so much attention applied to so many areas of the new GSXR it is no surprise the bodywork has undergone a major styling exercise, and this year’s bike is a lot slicker looking in my unstylish mind. According to Suzuki it is supposed to be more emotional however that is supposed to happen, but I have to say it does look a lot fresher. Taking some styling clues from the GSXR1000 it sort of builds on the theme and takes it off in its own direction, differing from the 750 only in some color changes on the bodywork and the forks. Up front the nose of the bike is sharper and the air ducts are moved 16mm closer together for improved aerodynamics. The headlights are vertically stacked, and the taillights are new LED units with integrated turn signals in the tailpiece. Up front the turn signals are located in mirrors.

Hopping on the bike for my first ride, I immediately noticed how the bike felt roomy as I adjusted the brake lever and familiarized myself with the controls. The foot pegs are actually adjustable, but I didn_t feel the need to make any changes. Offering a total of 14mm travel up or back, this is a nice option as we all most definitely come in different shapes and sizes. In the cockpit area, gauges are similar in shape to the older model, although the analogue tachometer faceplate is white this year and the digital speedometer readout is larger. It also has a shift light and gear position window, which I found it to be a real help for grabbing a quick double-check to see gear the bike was in exiting turns.

At the start of each track session a lead rider would take each group of journalists on a couple of sighting laps. This was useful for those of us who had never seen the track, and also because it was the only time we got to ride the bike at anything less than full throttle. Pulling strongly from low down the rev range, from my seat of the pants estimation would say it is a good bit stronger than the R6 before you hit double digits on the tachometer. As the speeds picked up this definitely helped those times when I should have been a gear lower, and by session number three Philip Island was unraveling through the windshield as the perfect motorcycle playground.

Honking down the front straight my initial feeling was confirmed, as it was easy to get most of my body out of the wind without feeling cramped up. For a bike that is physically smaller this year, the ride position doesn’t appear to be compromised one bit. Power is strong all the way through the range, with no real hit as it climbs toward red line. Just a strong, solid power and an intoxicating shriek from the muffler, which is easier to hear being closer to your ears.

All the important little details you need for fast laps are in place. Superb brakes with great feel, slipper clutch for those botched downshifts at 140mph and lighting quick steering with no loss of stability. Howling into Honda corner, the hardest braking spot on the track, was so controlled, I was able to run deeper and deeper in without problem as the laps unfolded. Then, exiting toward Siberia showed the bikes ability to get back on the gas, before tipping into the next left. Two gear shifts later running through the extremely fast turn 8, or the Hayshed as it is called, the bike was starting to run out a little wide, but it was the only place on the track I encountered this. Any problems this gave were soon forgiven though as I rolled off, dropped a gear without braking and slammed the bike on its side for Lukey Heights. As one of the most exiting corners on any racetrack around the world, coming over the blind rise hard on the gas leaned over as far as you will ever be is a huge leap of faith, and kudos to the bike for instilling bucket loads of confidence for his maneuver. Parking up at the end of the day, the best way round Philip Island etched fairly firmly in the gray matter, all that remained to do was get some rest to come back the following day to see how the 750 behaved. What I didn’t know was how much this would reveal about the 600.