Suzuki GSX-R 750

The 2008 Suzuki GSX-R750 features the same trio of halogen horizontally-mounted lights as the 2008 Suzuki GSX-R600, with the same vertically-stacked ‘position lamp’ to keep the traditional GSX-R look.

The 2008 Suzuki GSX-R750 has a new 750cc engine, with a big bore, short stroke; and a 15,000 rpm redline. It benefits from ram-air induction via two fairing inlets, with a six-speed, close-ratio gearbox, and a back-torque-limiting clutch. The 2008 Suzuki GSX-R750 also has three-way, on-the-fly engine mapping, as with the Suzuki GSX-R1000 and 2008 Suzuki GSX-R600.

There is a 125 gram lighter rear subframe, with an adjustable Showa rear shock, and inverted Showa forks at the front. The footpegs are also adjustable, and the 2008 Suzuki GSX-R750 comes with a steering damper reactive to speed. Lighter wheels save 430 grams despite keeping the dimensions of the previous model, there are 320mm front discs with radial-mount opposed-four-piston Tokico calipers, and a 220mm rear disc in a single-piston Tokico. Lastly the fuel tank is expanded to 17 Litres .

New Engine

• New larger 41mm ventilation holes between cylinders to reduce crankcase pressure and mechanical loss
• New electronic fuel injection system features Suzuki Dual Throttle Valve (SDTV) system - with dual fuel injectors per cylinder and new compact 8 hole, fine spray injectors for improved fuel atomization.
• New S-DMS engine management system allows the rider to choose from three engine settings to match riding conditions with a handlebar mounted switch
• Under deceleration the back torque limiting clutch reduces pressure on the clutch plates for smoother downshifting and corner entry
• New clutch cover and oil pan feature new internal ribs for increased rigidity and reduced engine noise
• New Idle Speed Control (ISC) system for improved cold starting, consistent idle quality and reduced emissions
• New high volume Suzuki Advanced Exhaust System (SAES) with an innovative under engine chamber leading to a new large volume muffler with a new distinctly shaped triangular silencer
• New hydraulic cam chain tensioner automatically adjusts while reducing noise and mechanical losses.
• New Ignition coil outer diameter is smaller for reduced weight and the starter motor uses new rare earth magnets for a compact lightweight design
• New 32 bit ECM features 1024 kilobytes of ROM for maximum engine performance working in conjunction with the new S-DMS engine management system
• The 2008 GSX-R750 features a sharp new look utilizing a bold new headlight design, new angular tail section and compact overall layout
• New electronically controlled steering damper uses a solenoid valve to move a tapered needle reducing or increasing oil flow to adjust damping force.
• New lightweight cast aluminum wheels featuring a new angled spoke design for improved rigidity, reduced unsprung weight and improved acceleration
• New Inverted 41mm Showa cartridge front forks are fully adjustable for high and low speed compression, spring preload, and rebound damping
• Radial mount four piston front brake calipers works with new thinner 310mm front brake rotors and a revised front brake master cylinder
• New GSX-R750 fuel tank features an innovative new design and fuel capacity is increased to 17 Litres

Engine Features

• Updated Compact 4-stroke, 4-cylinder, liquid-cooled engine designed for optimum combustion efficiency and maximum power delivery
• Cylinder head with narrow valve angles creating a compact combustion chamber design, 12.5:1 compression ratio, large intake and exhaust ports for optimum intake and exhaust efficiency and new Iridium spark plugs
• Lightweight titanium valves with steel alloy springs and aluminum spring retainers operated by thin-wall hollow camshafts to reduce weight and inertia
• Lightweight forged aluminum alloy pistons with short skirts, cut away sides and an anti-friction surface finish along with shotpeened chrome-moly steel connecting rods for improved strength
• Crankshaft features forged steel construction and a secondary balancer shaft for reduced vibration at high rpm.
• Crankshaft and transmission shafts are positioned to create a compact engine design and the engine itself is rotated slightly forward in the chassis allowing for straighter and shorter intake and exhaust ports
• High capacity large trapezoidal-shaped radiator provide efficient engine cooling - includes compact cooling fan assembly designed for improved air flow
• SRAD ( Suzuki Ram Air Direct) force feeds cool, pressurized air into the airbox at highway speeds, improving engine efficiency and throttle response
• The lightweight frame is built entirely of aluminum alloy castings and is engineered to deliver optimum rigidity, unmatched accuracy and maximum cornering performance.
• A braced aluminum alloy swingarm features a large 22mm swingarm pivot and is designed for optimum rider feel and maximum rear wheel traction
• Innovative rear suspension linkage utilizes a forged aluminum alloy link and a forged aluminum link rod that reduces side loads and helps the rear shock absorber move in a smooth arc
• Showa 41mm aluminum alloy rear shock with a 16mm rod diameter are fully adjustable for high and low speed compression, spring preload and rebound damping for maximum rider control
• Three way adjustable footpegs now feature die-cast construction and can be moved into three different positions with a 14mm horizontal and vertical range
• Compact, lightweight instrument cluster features a step motor controlled analog tachometer, LCD speedometer, dual trip meters, clock and a convenient gear position indicator

Review

There's nothing like a head bobbing, engine wailing, 140 mph fifth gear corner to get the blood stirring. Especially when that corner happens to be Turn 8 at the "Fastest Road in the West," on OE street tires. That's the scenario we found ourselves in at Willow Springs International Raceway behind the windscreen of Suzuki's updated GSX-R750.

Suzuki invited MotorcycleUSA to spend some time aboard their not too big, not too small, but instead what could be the perfect sized GSX-R. Despite the not too dissimilar appearance compared to the bike of yesteryear, the '08 750 hosts a number of updates that on paper seem pretty trivial. However, in function they are quite noticeable.

In an age when 600s and 1000s are a sportbike enthusiast's primary choices the 750 has faded away, replaced by either: a) fast enough for most, but still relatively tame supersport, or b) a triple-digit speed wheelieing literbike rocket, which has more power than most compact cars. Between those two extremes is where the Gixxer 750 finds itself idyllically placed. Although it lacks any direct competition, Suzuki continues to reengineer their original 20th century Superbike. For this year the engineer's aim was to increase the three most fundamental aspects of a sportbike: engine, braking and cornering performance.

Like its smaller displacement brethren, the 750 sports all-new, identical looking bodywork that Suzuki claims reduces overall drag, yet still maintains optimum wind protection for the rider. A new reshaped headlight uses three separate side-by-side light beams. The center 55W halogen beam functions as the low beam, and is bordered on either side by a brighter 60W multi-reflector halogen high beam.

The ram air intakes have been moved closer together where air pressure is the highest and the old wire-mesh intake grates have been replaced with a louver-type setup which straightens air flow enabling the airbox to achieve higher pressure. The fuel tank has also been modified and now more closely resembles the one on the GSX-R1000. Fuel capacity has received a slight bump as well up to 4.5-gallons (from 4.4-gallons.)

The tail section looks slightly flatter and has integrated LED brake and taillights between the built-in turn signals. The instrument cluster is as familiar as before, but has a slightly updated look. A large analog tach, digital LCD speedometer, trip meters, reserve fuel meter, gear indicator, programmable shift light, and bright, legible warning lights are all right there as well as Suzuki's versatile A-B-C three position Drive Mode Selector (S-DMS) indicator.

Underneath the sharp new bodywork is essentially the same 749cc liquid-cooled Inline-Four. Engine vitals like the 70.0 x 48.7mm bore/stroke, 12.5:1 compression and 29mm intake and 23mm exhaust valve size all remain the same. What has changed is the intake camshaft, which now features slightly less lift for increased mid-range performance. Larger ventilation holes linked between cylinder bores allow air trapped beneath piston stroke to be purged more quickly thereby reducing internal pumping pressure and mechanical power losses.

Engine fueling is achieved via Suzuki's Dual Throttle Valve (SDTV). The primary butterfly valve is controlled via the rider's wrist, while the secondary valve is controlled via the engine management system and helps smooth throttle response. Two of the four downdraft double barrel throttle bodies are new and all incorporate dual fuel injectors bestowed with 8 holes, twice as many as last year, which help to produce a finer fuel spray for more efficient combustion. The primary fuel injector has also been placed at a steeper angle and aimed directly at the intake port. New 10mm NGK sparkplugs provide a hotter spark igniting the finer fuel mixture. Controlling the engine's more complicated processing requirements is a smaller, more powerful digital engine control unit that utilizes a 32-bit microprocessor and 1024 kilobyte of ROM.

One of the most noticeable changes is the replacement of the ultra-trick MotoGP-inspired shorty silencer by a larger triangular-cross-section muffler which proved necessary in order to meet ever toughening government sound and emission regulations. A butterfly valve resides inside the exhaust and helps negate the performance-sapping catalysts that facilitate Euro 3 and Tier 2 EPA emission standards. Although the exhaust looks rather unsightly on the computer screen, in real life it actually looks pretty cool.

The chassis of this year's 750 is largely unchanged with the exception of subtle tweaks to the rear subframe, fork, shock, and steering damper. The rear subframe is now of lighter, more simple construction. The 41mm Showa inverted fork features updated internals and now incorporate both high and low speed compression damping adjustment in addition to preload and rebound adjustment which together allow for more precise suspension tuning. Gone is the fork surface treatment that distinguished it from the 600. The Showa rear shock also features internal updates and, like the fork, is now four-way adjustable.  the 70.0 x 48.7mm bore/stroke, 12.5:1 compression and 29mm intake and 23mm exhaust valve size all remain the same. An electronically controlled steering damper is tucked away neatly above the lower triple clamp. A solenoid valve controlled by the engine management system varies oil flow for easier steering at lower speeds and increased damping force at high speeds.

In the braking department up front, dual radial-mount Tokico four-piston calipers feature staggered piston sizes (32mm and 30mm) and grab onto a pair of slightly slimmer (down from 5.5mm to 5.0mm) 310mm diameter rotors. The front discs are attached via 12 floating pins instead of the eight used previously for increased heat dissipation and to help combat warping. A new master cylinder with a smaller 17mm bore (down from 19.05mm) pushes brake fluid through smaller diameter brake lines. This helps to increase brake input leverage as well as feel. A single piston Tokico rear caliper latches on to a 220mm rear brake disc.

The 750 rolls on redesigned cast aluminum wheels that are slightly lighter and more rigid due in part to the offset three-spoke design in which the spoke curve matches the direction of spinning wheel. Wheel sizes remain the same at 3.5 x 17-inch up front, and 5.5 x 17-inch in the rear shod in specifically engineered Bridgestone BT-016 rubber in sizes 120/70 front and 180/55 rear.

After recently sampling the '08 GSX-R600, I was excited to see how an extra 150cc's of engine capacity would increase the fun factor. Sliding into the low 31.9-inch saddle revealed the same comfortable ergonomics that make me feel at home on any of the three GSX-Rs. The bars aren't too low and foot pegs not overly high and overall the riding position is a great compromise between track and street.

Accelerating out from pit lane and onto the 2.5-mile road course the extra displacement can be immediately felt. Where the smaller GSX-R takes a bit to spool up, the 750 is already coming alive from as low as 7000 rpm. Keep the throttle pinned and the tachometer moves rather wildly towards its 15,000 rpm redline. Things never feel out of hand though, as the 750 makes a steady stream of useable, un-intimidating power. Induction noise sings in unison as the rpm's climb but doesn't sound quite as raspy as the 600.

When you're blasting in excess of 140 mph wind protection or lack there of really makes a huge difference and we're happy to report that the wind protection offered by the front fairing and windscreen is just as stellar as before. We were totally comfortable behind the windscreen and didn't experience too much unpleasant wind buffeting despite slightly windy conditions.

Historically, the 750 has always possessed tall gearing, and this year's model continues with the trend. Fortunately, the engine has the muscle to pull the gears and out on the ultra-fast Willow road course, gearing seemed especially well matched to each of the nine turns, with the rider only having to choose from second through fifth gears.

One might assume that the extra mph the 750 achieves over the 600 might be detrimental to its stopping capabilities. However, braking proficiency is just another one of the Seven-Five-Zero's many attributes. Similar to the 600 and 1000, initial bite is a bit on the soft side, however feel is phenomenal - especially the deeper you get into the lever. And if more stopping power is required just pull back a bit harder on your two right-hand fingers. Willow big track isn't known for any particularly hard braking areas, nonetheless, we experienced not even the slightest amount of brake fade.

GSX-Rs have developed a reputation for having wonderfully performing slipper clutches and this unit continues to impress. A revised drive cam shape and updated clutch plate material help increase the already tremendous amount of feel at the clutch lever. Although we couldn't really notice an increased amount of feedback, clutch lever pull felt as light as ever.

Although Suzuki didn't release any hard tech specs on the updated Showa fork and shock, in application the new suspension performed much better over the previous generation. Feel has been significantly improved even through the stock Bridgestone BT-016 tires. This allows the rider to be able to get a better read on what is happening beneath them and allowed us to comfortably flirt with the adhesion limits on the versatile Bridgestone street tires. Spring rates were a little on the soft side for a more aggressive 180-pound rider, but with the versatile range of adjustment, they were still plenty capable of delivering both an enjoyable and controlled ride at speed.

Despite the chassis geometry remaining the same, the Suzuki did feel like it changed direction a bit more responsively than its predecessor. This might be due to the use of the electronic steering damper, which at slower speeds and in the pits couldn't even be detected, yet completely quelled headshake when exiting hard on the gas over and through Turn 6's blind rise.

In spite of the larger exhaust muffler, cornering clearance is still as plentiful as ever and like before, the riders footpegs are adjustable and can be moved in three directions within a 14mm horizontal and vertical range. We left ours in the stock setting and experienced no footpeg grinding, yet we weren't at all cramped.

Based on previous experiences 130 horsepower, 140 mph, a corner, and OE street tires mix about as well as Red Bull and milk. However, at Willow, on the best 750 that's ever been manufactured, they blend perfectly. Even though engineers didn't make all that many changes, the modifications they did make were well focused and extremely noticeable. For us the $10,599 MSRP GSX-R750 is simply the perfect GSX-R.

Source motorcycle-usa.com