Suzuki GSX-R 750 K4

General overview of main features

* Compact & lightweight 4-stroke, 4-cylinder, liquid-cooled engine refined for overall weight reduction, improved combustion efficiency and power delivery.
* Redesigned cylinder head featuring a smaller combustion chamber, increased compression ratio, 2% larger intake ports and 2mm larger exhaust ports for improved intake and exhaust efficiency and increased power output.
* Lightweight titanium valves with steel alloy springs and aluminum spring retainers operated by thinner-wall hollow camshafts to reduce weight.

* Lighter weight forged pistons with chrome-nitride-coated upper compression rings and oil control rings for a harder, more consistent ring finish and reduced friction.
* One-piece cylinder block and upper crankcase section is equipped with ventilation holes between cylinders to reduce crankcase pressure and mechanical loss.
* New tapered, double-barrel throttle body design features Suzuki's SDTV throttle valve system, plus multi-hole-type injectors for optimum fuel atomization and throttle response
* Hydraulic cam chain tensioner fed by new internal oil passageway system - external oil hose eliminated to reduce weight.

* Faster 32-bit ECM with larger ROM memory and new 22 trigger-pole rpm sensor to provide more precise control of fuel and ignition systems - all housed in a smaller/lighter control box
 * Lighter weight stainless steel exhaust system featuring a higher capacity muffler with titanium core pipes and aluminum outer sleeve
* Reshaped radiator with 12% more cooling capacity, plus new style cooling fan assembly designed for improved air flow
* Larger oil cooler with 10% more oil cooling capacity
* Close-ratio, six-speed transmission and cable-operated clutch

New Chassis
* Aggressive new bodywork with less frontal area, plus ram air intake moved closer to center for higher airbox pressure and intake efficiency
* Vertical-type multi-reflector headlight, plus compact LED taillight and more aerodynamic turn signals
* Compact instrument cluster features a step-motor-driven analog tach, digital LCD speedometer and programmable rpm indicator light - also includes LED indicators for turn signals, high beam, neutral light, coolant temp, oil pressure and fuel level
* New aluminum frame with extruded main spar design similar to GSX-R1000 for optimum balance of size, weight and rigidity - includes new sub-frame mounting points
* Aluminum swingarm with extruded main arms and cast cross brace for torsional strength and minimal weight

* Compact 17-liter fuel tank - 10mm shorter and 20mm narrower at the rider's knees for easier rider movement and weight transfer
* Inverted Showa cartridge-type front fork with 43mm inner tubes and fully adjustable damping and spring preload
* Inverted Showa cartridge-type front fork with 43mm inner tubes and fully adjustable damping and spring preload
* Fully adjustable Showa piggy-back shock absorber with larger diameter shock piston rod for improved damping performance
* Radial-mount 4-piston brake calipers for improved braking performance - calipers are lighter and more efficient allowing for smaller/lighter 300mm rotors - system includes radial piston front master cylinder for improved brake lever feel
* Dual-opposed-piston rear brake caliper indexed to the swingarm - eliminates conventional torque for further weight reduction
* Lightweight cast aluminum wheels and high performance radial tires

Suzuki’s newest GSX-R redefines a classic
by Grant Parsons

There is a sound the wind makes around 170 mph—not so much a howl as a jet-engine whine.

As I circulate around Suzuki’s test track in Ryuyo, Japan, I hear that sound every couple of minutes.

Tucked behind the bubble, throttle pinned as the 2-kilometer straight stretches out ahead of me, I focus on the track while the digital speedo runs toward the bike’s electronically enforced 299 km/h limit—about 185 mph—lap after lap. Even figuring in a bit of speedo error, that’s pretty impressive.

Even more amazing: I’m on a 750.

Not just any 750, of course. The bike that’s screaming so willingly toward redline here is the 2004 GSX-R750. Its the latest production model in a line that revolutionized the sportbike world in 1985.

Back then, the 750 class was the pinnacle of motorcycle technology, with factories dumping large amounts of cash into development of the bikes that served as the basis of their Superbike racing efforts. It seemed that 750s would rule forever. But then came the ’90s, when nimble 600s and powerful 1,000s carved away the 750s’ niche.

Now, here we are in 2004, and the GSX-R750 has the distinction of being the only three-quarter-liter pure sportbike you can buy today.

Ah, but it also has the distinction of being the most highly advanced example of a very illustrious breed. And that makes it one impressive motorcycle.

Suzuki engineers think the 750 format still offers an optimal balance between power and weight. And after two days on the bike at Ryuyo, it’s hard to argue.

The new-from-the-ground-up 750 Gixxer was developed in concert with the redesigned GSX-R600. In fact, the new 750’s dimensions aren’t just similar to the 600’s, they’re identical.

Indeed, while the 750 frame is designed to be a bit stiffer (and, OK, the wheelbase is 5mm longer), the only visible difference between the two is the displacement sticker on the tail section. Suzuki officials confirmed that you could even swap engines between the two—the engine mounts line up. But why would you, since Suzuki has already done the heavy lifting?

That parallel development means the new GSX-R750 comes in with a claimed dry weight of 359 pounds—about 6 pounds less than last year and only 5 pounds heavier than the 600. Yet with a claimed 145 horsepower at 12,800 rpm (15 ponies more than the 600), it offers a significant power advantage, both in mid-range and up top, thanks to a host of engine changes that include just about everything but the bore and stroke of the motor.

Reciprocating weight and mechanical losses are reduced through titanium valves, plus lighter valve springs, camshafts and pistons. The compression ratio has been bumped from 12:1 to 12.3:1. And the forced-air induction ports are closer to the centerline of the bike for more charge.

Looking for more changes? The fuel injectors have been reoriented, and the nozzle heads feature more holes. The ignition gets a faster computer. Muffler volume is increased. And though I’m usually not one to rave about a radiator, the all-new trapezoidal unit on the 750 not only has 12 percent more cooling capacity, it’s gorgeous.

The other big change to the 750, of course, is a significant downsizing and streamlining of the overall look, which updates the bike’s aggressive posture nicely.

The new bike sports a narrower fairing (by 43mm) and tank (by 30mm). Thanks to a shorter tank and lower seat, you sit 15mm closer to the bars and 5mm closer to the ground.

Up front, the headlights are now stacked for a more Hayabusa-esque look. In back, the tail section is updated with LED taillights and a more streamlined shape. A new, blacked-out swingarm and frame round out the package.

On the track, all those changes work extremely well together. There’s no big-bike feel. No surprises in corners. Just nimble manners and good power.

The difference between the 750 and the 600 it resembles becomes obvious when you twist the throttle. Far from being intimidating, the extra power is intoxicating. Whether you’re starting an early drive toward the next corner like a pro, or suddenly finding yourself a gear too high like a novice, the extra ponies will bail you out.

The Ryuyo track is a proving ground used to test motorcycles, not a racetrack, and it has tight walls close to the track all around. It’s the kind of place where a handling quirk or power glitch will quickly toss your heart into your throat. Not surprisingly, the GSX-R felt at home here, displaying the flawless track manners you’d expect from a championship-level machine.

We got two days of track sessions aboard the 750, and on the second day, the region’s strong crosswinds howled. That should have made the wide-open back straight a wicked feat of daring, but the Gixxer’s predictable manners kept the drama to a minimum.

In the end, I came away impressed. Far from being a styling exercise that banks on the legendary GSX-R750 name, the ’04 version is a full-on redesign that truly represents the continued development of the highly advanced 750 line.

The new GSX-R750 is priced at $9,599—$1,500 more than the ’04 600. That could be a major factor for some buyers, but consider this: That extra grand and a half buys you better suspension in the form of an inverted, cartridge-style fork and 15 extra horsepower you’d be hard-pressed to find for that price in the aftermarket.

Long live the 750!—Grant Parsons

Source Amadirectlink.com