Wednesday, 7 December 2011

Suzuki GSXR 600 2004

A lightning-quick glance shows 150 mph on the digital speedometer with the tachometer needle hitting redline at 15,500 rpm in fifth. It's a not-so-balmy 37 degrees, and I am working overtime at hiding as much of my vented leathers behind the GSX-R's narrow fairing as possible. Willing some blood into my frozen fingers, I roll off the throttle and onto the brakes, sliding rearward to keep the rear wheel on the floor. Downshifting, I dive left for the horseshoe and rail round on a steadily increasing throttle, before nailing it back up to the redline. Briefly hitting the rev limiter it is time to get hard on the brakes and drop a gear for the tight uphill right-hander that leads to the first of Misano's two chicanes. 

Hanging way off to keep the tires as upright as possible, I feed in the power and hold the same gear up the hill, before sending brake fluid to the eight pistons down at the front wheel. Clipping the curb into the chicane, I effortlessly flick the bike left for the run up to the top horseshoe. Third gear ends a tad bit short of the corner, but to save two shifts I hold it on the limiter before arcing through the corner. Accelerating to the redline up the short straight brings the approach to the second chicane. As with the first, it is possible to take this a lot quicker than the brain will at first allow. A good drive has the bike screaming onto the front straight, knee puck skimming the tarmac as I attempt to use the entire racetrack and ignore the concrete way three feet to my right. 

The Guts

Taking the big bird to Italy for the launch of the 2004 GSX-R600, I have plenty of time to think about the new bike. Lighter and more powerful this year, it comes with titanium valves, an inverted fork and radial brakes, to mention just some of the changes meant to vault it ahead of four contenders that debuted all-new last year, demoting the old Gixxer to also-ran status. 

Starting with the chassis, the Gixxer gets an all-new, thinner aluminum twin-spar extrusion frame. Rake, at 23.25 degrees, is a bit steeper than the 24-degree figure of the '03 model; trail is down slightly from 96mm to 93mm and the 1400mm wheelbase remains the same. Finished in satin black, the frame also differs from last year's bike with the removable aluminum subframe attaching directly to the frame. The seat rails are now made of cast aluminum, as is the cast bridge that runs between them, and the whole plot is said to be more crash resistant.
You can say one thing with absolute certainty about the GSX-R: its one tough machine.
With the suspension dialed in the GSX-R was a carving machine on the curvy track.
The new swingarm looks like last year's swingarm with braces welded on top, and it shares the same length, height and width, so maybe it is? The welds are actually very smooth, and the unit looks extremely butch holding the chunky 180-series tire in place. Up front, Suzuki has chosen a Showa 43mm inverted fork for increased rigidity and overlap. Fully adjustable for all the usual stuff, I only made a few changes on the second day as my speeds began to increase. The overall suspension settings were actually remarkably close to showroom stock, with the exception of a little extra preload up front to deal with the high-speed braking at Misano. The rear shock itself is a 46mm Showa unit, and differs from last year's with a thicker diameter internal rod, as well as being slightly shorter. Adjustable for the big three, it performed flawlessly over the two-day test.

At the bottom of the inverted fork, the GSX-R600 rolls on the same 17-inch three-spoke alloy wheels as last year's model running the same 120/70 and 180/55 front and rear sizes. The bikes we rode came equipped with Bridgestone BT014SFs, but Dunlop D218s will be fitted for us here in America. Full marks to the Bridgestone tires. With cold winds blowing across the Santa Monica raceway, they gave a whole lot more grip than I had originally thought possible. 

This year's front brake discs are 20mm smaller at 300mm and 0.5mm thicker, losing 20 grams in the process. Suzuki uses Tokico radial-mount 4-piston calipers that allow for more rigidity and improved braking. Lightly squeezing on the six-way adjustable lever at over 150 mph scrubbed off the required speed to enter the horseshoe with absolutely no drama - the brakes just progressively getting stronger the more I pulled. Riding the same bike for both days, the brake action was just as strong during the last session as it had been during my first. Partly responsible for this incredible setup is the radial-piston front master cylinder. Unlike a conventional piston that works horizontally against the lever, the radial piston is positioned vertically, allowing a more direct force from the lever to the piston. This gets more fluid to the brake calipers and is said to improve feel and feedback.

Responsible for all the high-speed forward motion, the fuel-injected GSX-R engine has undergone a total redesign in the quest for more power and less weight. Suzuki claims 4% more power, and says it has 124 horsepower with the assistance of its ram-air system working at its max. Peak torque is now listed as 3% stronger. Reciprocating weight inside the motor is reduced by 5% thanks to titanium valves, lighter pistons, camshafts, valve buckets and more. Displacement, bore and stroke are unchanged, but compression ratio has increased to 12.5:1 from 12.2:1 with the use of flat top pistons and a more compact combustion chamber. 
2004 - Suzuki GSX-R600
Street hooligans and track junkies alike will be pleased with the radial-mounted Tokico brakes.
Providing the titanium valves a home, the new cylinder head has been through the total re-design process, now weighing in 80 grams lighter. As part of this diet, the cylinder-head bolts have been reduced 3.5 grams in weight for a total saving of 35 grams, and the cam housing bolts 1.4 grams for a further 28-gram loss. This weight loss program continues into the camshafts, valve springs, and valve buckets. Connecting rods 3mm shorter attach to a new crankshaft that features slimmer journal diameters, 30mm instead of 32mm. This is to optimize crankshaft balance and to reduce mechanical friction loss. Looking into the gearbox shows closer gear ratios and a totally redesigned shift fork. I have no complaints about the shifting on the bike using only the clutch for downshifting, the bike effortlessly selecting the next ratio whenever needed. The non-adjustable cable clutch is very light, with a 25% reduction in the spring rate. Initial load has been raised by 4% to deal with the engine's extra power. 

Visually, the bike certainly shows its GSX-R heritage and has been styled this year for a more aggressive look. Up front, the vertically stacked headlights replace the old side-by-side jobs and sit in a narrower, more aerodynamic fairing. The two-stacked headlights consist of a projector-type on the bottom for low beam and a multi reflector type up top for the main. Even the GSX-R's turn signals have been given a new more aerodynamic shape, as well as being lighter.

The gas tank is narrower and shorter this year to make life easier for the rider during cornering transitions or getting hard on the brakes. The seat serves as a useful work platform to slide on and off the bike, while giving enough room for my near six-foot frame. Looking oh-so-cool behind the seat is the tight-looking tailsection, with two sets of seven LED lights sitting on top of each other. 
2004 - Suzuki GSX-R600
Yes, it's lighter, even with the body work.
Shifting at 15,500 rpm through the next two gears and wide open in fourth gear, it is necessary to lose a lot of speed for Misano's tight left-hander. Lap after lap I mess up, tipping the bike in while still on the brakes. It doesn't violently protest, but it makes for some heavier steering effort and a little awkwardness as much of my body weight is on my arms. Sliding off the seat to the left, I accelerate towards the series of fast left-handers that lead to the long back straight. Flat out up to the first corner before short shifting through the second, I briefly stand the bike up and take one more quick shift before exiting the corner around 120 mph. Tucking in and stretching the throttle cables, it is soon time to get back on the brakes at over 150 mph.

Off the brakes, while pitching into the horseshoe one more time, I twist the throttle back up to redline, indulging in the intoxicating intake roar that resonates as the engine rips past 9000 rpm. Pipe howling its wonderful four cylinder magic, it's back on the brakes, shifting my weight for the tight up-hill right-hander. 
Inside my leathers I am sweating as I get more and more aggressive with the lithe 355-lb. (dry) GSX-R600 beneath me. All thoughts of the near freezing temperatures have faded as I lock my eyes on the next corner and wring the throttle as hard as I can before getting set up for the chicane.

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