Suzuki riders have been uplifted by Maverick Viñales’ win in the British round of MotoGP and by the MotoAmerica Superbike wins of Toni Elias and Roger Hayden this year, but a new GSX-R1000 has been a long time coming—the last engine update was in 2009.
Now it’s revealed—the all-new 76.0 x 55.1mm inline-four redlines 1,000 rpm higher at 14,500, is carried in a MotoGP-inspired chassis, and has the full suite of modern race-developed ride-by-wire electronics plus (for the R-model) Showa’s Balance Free suspension.
I flew to Japan to see the GSX-R presentation and track testing at Suzuki’s seaside Ryuyo circuit. These intros aren’t easy; the flight hours are long, and busy lead engineers, required to sit through our questions, would surely rather be in the dyno cells or writing code. For us journalists, the excitement is in the unfolding—realizing what the parts mean, what the numbers and dimensions have to tell. And in being in Japan.
Suzuki’s obvious goal is to put the GSX-R1000 back on top by boosting engine and chassis performance, by cutting weight, and by helping the rider operate safely closer to the limit through a full suite of electronic rider aids. Etsuo Yokouchi, creator of the original GSX-R concept, said, “Make it faster by chassis design, turn it faster by engine design.”
Maximum acceleration is set by the point at which the front wheel lifts—add any more power and acceleration decreases as the bike stands up. Therefore the new engine is moved forward 20mm by cutting its cylinder angle from 32 to 26 degrees. The new chassis, which is 10 percent lighter than the previous design, wraps around the clutch on the right to move the swingarm pivot forward, allowing use of a new 40mm-longer swingarm.
Engine width sets the ultimate limit to cornering; even though cylinder bore has increased from 74.5 to 76mm, crank-level engine width is reduced 6.6mm, and distance between frame rails has shrunk 20mm. Cylinders are “siamesed,” meaning they are joined as one, with no coolant passing between.
Increased and wider-range performance is the overall engine goal. Suzuki’s business is sportbikes, so making GSX-Rs easier to ride broadens their sales appeal. Therefore increasing peak power was only part of the job; the rest was to make that power easier to use by providing stronger bottom and midrange performance. Cosworth and BMW both built close to 300 hp into three-cylinder 990cc MotoGP prototypes, but they were unrideable. The winning play on two wheels is to give the rider confidence through controllable power that gets more out of a motorcycle’s rear-tire footprint.
Suzuki’s “Broad Power System” for this new GSX-R has four elements. The first is conversion from the previous inverted-bucket-style valve tappets to tiny finger followers. This, by minimizing valve train weight and making pointy cam lobe shapes unnecessary, allows use of the short valve timing that generates wide torque, plus the high lift that boosts power. The shorter the timing and higher the lift, the higher the valve acceleration must be, which in turn requires minimum valve train mass. An engineer commented that while future increases in cam lift would require larger-diameter bucket tappets (to prevent the cam lobe from touching the edge of the bucket), finger followers easily adapt to higher lift.
Broad torque is good news, but “where’s the beef?” To get class-dominating straightaway power, this engine utilizes the “SR-VVT” centrifugal variable intake-cam timing system (which Suzuki has used for 10 years in MotoGP) to delay intake valve closing after bottom center only at higher rpm. This gains top-end by letting high intake velocity rush into the cylinder longer. This compact device is built into the intake cam sprocket and consists of two grooved discs facing each other, with a steel ball in each groove. In one disc, the 12 grooves are radial but ramp-like, becoming shallower with increasing radius. But in the other they are angled. As engine revs rise, centrifugal force moves the balls outward, causing the cam to retard with respect to its drive sprocket. The two discs are pressed together by Belleville springs whose pressure, combined with the ramped ball grooves, tends to return the balls to their innermost positions at lower rpm.
This allows the engine to be cammed for broad torque, with peak power being boosted by a high-rpm delay of intake closure by a maximum of approximately 20 degrees.
How much power? The brochures we picked through as the Powerpoint images flickered on a screen said “max output—TBA” and same for max torque. But assuming this new engine peaks 1,000 rpm higher than the 2009–’16 model, which made a claimed 183 hp at 11,500, we can expect very close to 200 hp.
The third group of engine changes is the Suzuki Exhaust Tuning “SET-Alpha” system of exhaust pipe valves. Crossover tubes joining header pipes of cylinders one and four as well as two and three have been used for years, as they boost top power at a cost of torque loss lower down. In this engine, each crossover tube has a butterfly valve. The same motor that operates the crossover valves also controls a “noise valve” in the single collector, just before the large upswept muffler on the right. Engineers told us “two positions only—open or closed, no in between.” With the valves closed, torque is gained that would have been lost on previous “valveless” engines. Broad power goals at work.
A technician stood between two tables as we filed into the presentation, and he pulled wrapped goodies from a box and set them out for our inspection: intake and exhaust valves (exhausts are now titanium, and at 24mm a bit smaller than before to make room for bigger 31.5mm intakes), a tappet finger of just 3 grams effective moving mass (because it’s pivoted at one end), and the throttle body, complete with its throttle-by-wire drive motor. This is the fourth major system—opening so many possibilities. The previous dual injector/dual throttle-plate system is replaced by single butterfly throttles with primary injectors below them and showerheads (“S-TFI,” or Suzuki Top Feed Injectors) hovering above the open bellmouths, for which are claimed “higher peak power, more efficient combustion [more complete fuel droplet evaporation?], and more precise fueling control.”
The cylinder head features near 45-degree intake downdraft and greatly reduced cooling water volume to achieve the increased heat transfer of faster, more turbulent coolant flow. Another component of the “Broad Power System” is the bi-resonant molded plastic intake bells. Looking like a variable-length system with the extension bell just lifted off to leave a slit between bells one and four, this is claimed to resonate at its longer length at lower revs then resonate at its shorter length up high. Who knows? This might have been an accident—someone noticing this effect on the dyno with a prototype variable-length system stuck at its mid-position (“Uh, boss? Would you come look at this…?). Half an ounce of plastic in place of control motor, cables, guides, and movable bells.
Also on the table was a beautiful three-ring piston (two gas rings plus a two-rail-plus-expander oil ring). The extremely smooth crown and squish of this nine-cavity forging, with extra volume under the central spark plug, is clearly the result of R&D intended to accelerate combustion (the less time hot gas is held up against the head, the less heat can escape from it). The tiny wristpin—barely an inch-and-a-half long—transmits huge action; at peak combustion pressure that pin sends 9,000 pounds of force down through the steel connecting rod, into the crankshaft. As Mr. Yoshida used to say, “Necessary good quality.” Compression was 12.9 but is now 13.2. Compression boosts torque at all rpm.
Suzuki Clutch Assist System acts as a slipper clutch to limit engine-braking during deceleration and increases pressure on the clutch plate stack under power, allowing use of lighter springs giving a lighter clutch pull.
On the previous day, still tingling from 11 hours over the Pacific plus the thoroughly modern high-speed electric “Shinkansen” train from Tokyo to Hamamatsu, we visited Suzuki’s museum. Seeing the ruggedly constructed automatic looms Suzuki built as its first business (1909–on) I could understand the solid construction of the company’s early (circa 1952) motorcycles. Among mini-cars, 500 GP bikes, and production two-wheelers of every kind, only one of the company’s many wonderful 1960s 50, 125, and 250 GP two-strokes escaped the crusher, the 50cc 8-hp RM-62 ridden to Suzuki’s first-ever GP title by Ernst Degner. I stood and breathed in its historical force.
The old chassis paradigm was bridge-like rigidity, but this has famously led to reduced front-end feel and push. In line with current MotoGP practice, this new GSX-R chassis, with its more slender side-beams and uprights, plus longer, more flexible front engine hangers, provides lateral flexibility that builds confidence by keeping the front tire in more intimate cornering contact with the pavement. This has been intensively studied by Finite Element Analysis.
Suspension is Showa’s “Balance Free” system (featured on the upmarket GSX-R1000R, pictured below), whose design seeks to eliminate transient forces and sudden rates of change that are not only perceived as discomfort by the rider but can break tire traction. It does this by placing both sides of the damper piston under consistent accumulator pressure, using both sides of the piston to push fluid through external damping valves, one for compression, the other for rebound. Fluid displaced by damper rod movement is no longer used at extreme pressure to generate compression damping. Tires like smooth loading best.
Radial-mount Brembo Monoblock calipers each carry four 32mm pistons, pushed by a 14mm radial pump master cylinder. Brembo discs transmit braking force to their carriers through five T-drive and five button mounts. T-drive transmits brake torque without wedging the disc outward, while buttons give good control of axial disc location.
Wheels with six very slender MotoGP-style spokes replace the previous three-spoke design. The front tire is unchanged, a 120/70ZR-17 Bridgestone, while the rear gains an extra 5 percent in aspect ratio to become a 190/55ZR-17 Bridgestone RS10 series. Overall gear ratio is lowered to match the rear tire’s slightly larger rolling radius and the engine’s higher rpm of peak power. A lighter 525 chain replaces the 530 previously used.
After the presentation the engineers smiled for Kiwanis-style photos, standing behind a bike. On Ryuyo’s 7,500-foot straight the bikes were topped-out a long time. After they’d pass I could hear the endless Pacific surf. It was a privilege to be here, a guest of another culture, riding the 180-mph train, eating pork katsu, and getting a clearer idea of how GSX-Rs come into being. Suzuki’s very identity is in GSX-R, and this new bike looks like a very sharp sword.
Autoblip downshift on the R model…and more. A quick rundown of the digital superbike, 2017:
• 32-bit dual processor ECM
• Motion Track TCS (Traction Control System) has 10 intervention levels, or modes.
• Inertial Measuring Unit (IMU)—measures pitch, roll, and yaw.
• Suzuki Drive Mode Selector (S-DMS)—adapts throttle response to special conditions via three modes A, B, and C (B and C modes require more throttle grip rotation for a given torque).
• Bi-directional quick-shift system (on GSX-R1000R)—employs ignition retard to unload the gearbox during upshifts and blips the throttle during downshifts.
• Launch Control system (on GSX-R1000R)—rider can concentrate on clutch operation, reduces chance of wheelie, more consistent start.
• Suzuki Easy Start System—as in late-model cars, once you push the start button, the start cycle cranks the engine until it fires.
• Low RPM Assist (LRA)—once you have throttle by wire, the possibilities are endless! Most drivers today learned on automatic transmission cars, so shouldn’t clutch engagement on a motorcycle be “stall-proofed”? If engine revs drop during a start, this system makes snatching or stalling less likely. This is enabled through the ISC system (ISC = Idle Stepper Control), which supplies idle air to stabilize idle rpm.
• Motion Track Brake System (on GSX-R1000R)—when the IMU detects rear-wheel lift, the ABS unit immediately adjusts front brake pressure to reduce rear-wheel lift. When the front brake is applied while the motorcycle is leaned over, the ABS unit immediately optimizes front brake pressure.
• Full LCD multi-function instrument panel.
• All-LED lighting.
• Sensor suite; front-wheel speed, rear-wheel speed, crank position, gear position, throttle valve position, throttle grip position, IMU data stream.