Late Braking: Kawasaki ZX-10R, Yamaha YZF-R6, And More

Bike
Per the now-usual modus operandi of upgrading sportbike models every two years by the Japanese manufacturers, Kawasaki has revamped the ZX-10R substantially from its last '06 iteration, instilling a host of modifications aimed at re-establishing Team Green's prominence in the literbike class. The aggressive-looking new 10R appears to be a no-holds-barred design with numerous changes drafted in straight from the firm's Superbike and MotoGP racing efforts, with even more of a track focus than ever before.

The 10R wasn't the only big Kawasaki that was entering its two-year development phase, however. KHI engineers surely caught wind of Suzuki's new Hayabusa that is scheduled to be unveiled for '08, and couldn't let Kawasaki's flagship sportbike sit idly by and get one-upped by its main rival. A surprising boost in the 14's overall power (as if it actually needed it...) was accomplished via some subtle changes.

Even Team Green's little Ninja 250R wasn't left out of the upgrade parade. A number of changes to Kawasaki's original entry-level Ninja have taken it a step closer in looks and performance to its high-performance brethren.

ZX-10R
Like last year's ZX-6R, Kawasaki engineers employed the services of a top-flight racer to help with machine development. In the new ZX-10R's case, it was former World Superbike and MotoGP contender Akira Yanagawa, who still competes in the All-Japan Superbike Championship (in fact, at press time, he was a close second in the title chase with two rounds to go).

Because Kawasaki engineers wanted to keep the previous model's superb midrange power intact, bore and stroke remain the same with the all-new engine. A one-piece upper crank- case and cylinder casting shaves more than two pounds of weight and increases overall case rigidity, and the clutch and transmission shafts retain the stacked configuration to cut overall engine length front-to-back. Additional weight was saved by oil channels cast into the cases (replacing external oil lines), and specially designed internal fins in the liquid-cooled oil cooler improve its heat dissipation capacity. The oil pump gear ratio has been refined along with the aforementioned lubrication system changes to reduce drag and improve efficiency.

The crankshaft is all-new, and even though the overall assembly weighs about two pounds less than the previous unit, it still maintains the same inertial force. A new water pump using the same style impeller as the ZX-14 improves coolant flow with less friction, and a new-generation radiator with more tightly packed cores cuts weight and improves cooling.

Up top, the cylinder head features reshaped intake and exhaust ports (the exhaust ports are narrower in the midsection), as well as a redesigned combustion chamber for improved flow and combustion efficiency; compression ratio remains the same at 12.7:1. The exhaust valves themselves have shrunk slightly, from 25.5mm down to 24.5mm. Camshafts are more aggressive, with higher lift for better top-end power.

Induction is now handled by throttle bodies with an oval cross section (velocity stacks are oval as well), and two injectors per cylinder are now used for better overall response. The compact flat-style fuel pump from the '07 ZX-6R permits the same 4.5-gallon capacity as the previous fuel tank, despite the extra room needed for the new secondary injectors. The ram-air intake was redesigned to reduce intake noise and further improve flow efficiency into the larger airbox, which was also designed with better access and ease of maintenance in mind.

The six-speed transmission now features shorter 1st, 4th and 5th gear ratios, and the rear sprocket gains one tooth to further shorten the overall gearing; this would tend to reinforce the notion that Kawasaki engineers wanted to increase top-end power without sacrificing any of the previous 10R's stout midrange.

It appears that the underseat exhaust styling fad is now fading fast, as the new 10R joins the ranks of sportbikes using an under-engine chamber exhaust. A pre-chamber underneath the engine features a palladium catalyzer that allows the new literbike to pass ultra-strict Euro III emissions standards. A single "orthogonal" shape titanium silencer exits out the right side of the pre-chamber.

Of particular interest to us was the description of the engine's ignition system. The press kit describes the new ECU as having "complex program parameters based on extensive rider testing" that utilize an "advanced ignition management system that curtails sudden spikes in engine speed for improved rider control." This new engine management system monitors engine rpm, throttle position, gear position and "vehicle speed" most likely based on rear-wheel speed as measured at the countershaft sprocket. Is this a form of traction control or the basic foundation for one? Kawasaki U.S.A. reps were understandably mum on the subject when we inquired, so a more in-depth analysis will have to wait until we can talk to KHI engineers.

The chassis has been extensively reworked as well. In order to achieve the optimum rigidity "balance," certain pressed aluminum sections of the frame were switched from concave to convex shape to alleviate stress areas. The wall thickness of the swingarm pivot plates was changed to increase rigidity, with ribbing added to the interior of the plates where it joins the upper cross-member to "slightly slow down the frame feedback for a more accurate feel." The steering tube was moved forward 10mm and its length changed an undisclosed amount (again, for rigidity balance), and the swingarm pivot location was moved an undisclosed amount for a "slight front/rear weight balance change." The two-piece die-cast aluminum subframe is narrower and mounts directly to the frame's upper cross-member (instead of to the swingarm pivot plates) for "more direct rear suspension feedback to the rider." The new swingarm's pressed-beam construction was also tailored toward feedback and rigidity balance, with the bracing now back on top, ostensibly for stiffness (but more to make room for the under-engine exhaust, in our opinion).

Suspension-wise, the new 10R still has a 43mm inverted fork with DLC coating on the tubes for less stiction, but like last year's 6R, it has the springs mounted on the bottom to submerge them in the oil and reduce cavitation. The rear shock linkage has moved to make room for the exhaust, and the shock gains separate high- and low-speed compression damping adjustments. New radial-mount Tokico calipers still utilize four separate pads for increased initial bite and progressive feel, with the petal discs growing to 310mm from 300mm (and a corresponding shrinkage from 6.0mm to 5.5mm thickness) for improved braking performance. The five-spoke aluminum alloy wheels are lighter, courtesy of a pressure-casting technique that allows for less material with identical strength.

The new 10R's ergonomics have been designed to offer the rider "increased contact with the bike...[for] very accurate feedback regarding chassis performance and road surface." The fuel tank is flared around its top to make it easier for the rider to rest his outside arm on while leaning through a turn, and the seat is narrower at the front and shorter front-to-back. The bodywork follows the MotoGP "minimalist" design trend, with smaller fairing sides decreasing side wind susceptibility. Other nice touches include mirror stalks with pivots to decrease the possibility of tip-over damage and UV-blocking glass on the instrument panel to make the LCD panels easier to read.

ZX-14
Although the ZX-14 looks the same externally, some subtle internal changes result in significant performance advances, with the big Kawasaki getting a boost in overall power while still meeting ever-stricter Euro III emission and noise standards. In fact, one was actually a by-product of the other.

In order to meet the latest Euro III emission standards, a third honeycomb catalyzer was added to the exhaust system, positioned in the collector leading to the twin silencers (where the other two catalyzers are located). Because the collector had to be modified to accept the cata-lyzer, the connecting tubes between the primary headers from cylinders 1-4 and 2-3 were enlarged approximately 75 percent to compensate for the new collector shape. The silencers themselves were redesigned, with the first and third chambers' capacity modified, along with the lengths of the pipes protruding from each baffle plate. Also, the secondary air-injection ports in the cylinder head were made 20 percent larger to handle the increased flow.

In order to increase combustion efficiency, the EFI injector angle in the throttle bodies was increased from 15 to 20 degrees to disperse the atomized fuel over a wider area. The intake ports were subtly massaged for improved flow. The intake and exhaust modifications resulted in a boost in overall torque across the rpm range, especially in the low end.

Reducing mechanical noise was achieved by revising piston profiles and adding a urethane insulation sheet inside the cam chain cover.

Switching to pressure die-casting in the portions of the monocoque chassis' formerly gravity-cast aluminum parts also allowed Kawasaki to shave some weight from the 14.

Ninja 250r
The smallest Ninja receives some long-needed upgrades, starting with revisions to the cams and a new 2-into-1 exhaust system that results in more low-end and midrange torque. The pistons feature reinforcement in the crown and pin boss area for improved durability, while the rings were redesigned to reduce oil consumption. The 250R now has a full fairing resembling its bigger brethren for improved wind protection and finally gets 17-inch wheels to allow fitment of modern sport rubber. A new 37mm conventional fork enhances overall handling, and the single front disc grows to a 290mm petal unit, providing better braking power.

Updated Yamaha YZF-R6
Bike
While Yamaha's little screamer was new from the ground up in '06, that hasn't stopped the company from making a host of changes for the '08 model, focusing on better throttle response from the engine and improved balance and performance from the chassis. The biggest change to the motor is the addition of YCC-I (variable-length intake funnels) to the throttle bodies, along with revised fuel mapping to match. Inside the engine, domed piston crowns bump compression from 12.8:1 to 13.1:1, and wider crank bearings headline more than 50 changes to reduce friction.

Detail updates to the chassis include a new frame and swingarm with "optimized rigidity and strength balance." The frame is thicker in the headstock and swingarm-pivot areas, and the cross-member has been eliminated. Likewise, the swingarm has been stiffened with the addition of ribs inside the cast arms and the rear portions changed from extruded to forged. The subframe is now magnesium as opposed to aluminum, reducing weight and improving mass centralization. New outer fork tubes are gripped by a bottom triple clamp that is 5mm thicker, and front disc thickness is up from 4.5mm to 5.0mm. Ergonomics have been revised slightly, with the rider positioned farther forward and the clip-ons lower, forward and re-angled. Finally, the R6's tires are a newer version of the original's OEM-spec Dunlop Qualifiers.

The bodywork has been changed for both styling and aerodynamics, and four color schemes are available: blue/white, raven, liquid silver and cadmium yellow with flames. The bike's official introduction is slated for early November at Laguna Seca; Trevitt and Kunitsugu are already fighting over who gets to attend. Look for a First Ride piece in an upcoming issue and the new bike in dealerships as early as November.

The only other significantly updated Yamaha sportbike is the FJR1300. Changes to the super sport touring bike include a lighter ABS system with improved lever feel, a new windshield coating for better scratch-resistance and a revised shape for the AE model's handlebar shifter. The FZ1 has further-revised fuel injection settings, and the FZ6 has a new matte black headlight cover-the only changes for those two models. The YZF-R1 and YZF-R6S return unchanged for '08, while the YZF600R has been discontinued.

Biperformance SHIFTFX
Uplifting Push-Button Shifting-Clutch Optional

Alternative transmissions-Honda's 1976 Hondamatic, Suzuki's 1982 Suzukimatic, Moto Guzzi's 1975 Convert and Yamaha's Chip Control Shifting in its '07 FJR1300AE-haven't exactly been among motorcycling's success stories. And it's not hard to figure out why: Each one ended up trampling performance and rider control in the headlong rush toward convenience.

The ShiftFX system from Dean Pick's Biperformance Development Corp. (www.biper formance.ca) is different. Perhaps the closest analogies to the ShiftFX system are Porsche and Audi's Tiptronic transmission, BMW's SMG and a host of other so-called "manumatics" used in cars. ShiftFX offers the same kind of convenient push-button gear selection-in this case, with a three-button panel (green for upshifts, red for downshifts and black for neutral) mounted on the left clip-on of Biperformance's Honda CBR600F4i test mule I rode. But there's a big difference-ShiftFX still allows manual control of the clutch and shift lever.

ShiftFX (the street-based Gold version kit, which was on the CBR600F4i, retails for $1295; there are three other ShiftFX kits, but the Gold is most appropriate for sporting street riding and track days) functions via an on-board air compressor and tank that operate an in-line pneumatic clutch actuator (cable-only for now; Pick's working on one for hydraulic clutches) and a drag-racing-style air shifter. The clutch actuator and air shifter are controlled by means of a separate ECU spliced into the bike's electrical system. Combined additional weight adds up to a claimed seven pounds.

The ShiftFX system operates via a three-button panel on the left handlebar; green is for upshifts, red is for downshifts and the black button is to engage neutral. Note, however, that the clutch lever is still present; the rider can use the clutch and shift lever (in fact, he must in order to take off from a stop) to accomplish gear-shifting manually.

It takes a few minutes to get at least slightly accustomed to using your left thumb to select gears rather than your left toe. But once you make that hurdle, the ShiftFX works surprisingly well, exhibiting a precision that speaks of endless hours of testing and development. This is no crude attempt at push-button shifting-you can't help being impressed with how smooth and refined the ShiftFX system operates.

Shift action is handled by this pneumatic shifter unit, which actually alters its shift speed according to engine and gear selection. At slower speeds, lower gears and light throttle settings, the shift action is slightly slower to avoid snatchy gearshifts that could upset the bike's handling. The gearshift lever can be provided and operated manually if desired.

An on-board compressor and air tank supply pressure to operate the ShiftFX system. This air pressure gauge allows quick monitoring at a glance.

This inline pneumatic actuator controls clutch function via a piggyback ECU that reads wheel and engine speed to determine proper activation. For instance, if the wheel speed is below a certain threshold compared to engine speed, the ECU tells the actuator to release the clutch slower than usual, basically mimicking a slipper clutch. If the rider pulls the clutch lever, however, the unit releases all clutch function to manual control.

Push the upshift button, and the system completes the action for you in as quick as 75 milliseconds, quicker than most any human could do-and actually adjusts to how you ride. For instance, "ShiftFX will shift smoother and slower at lower rpm, lower road speeds and smaller throttle-openings," says Pick. And for downshifts, if the control unit senses that rear-wheel speed exceeds a specific figure compared to engine rpm, it signals the pneumatic clutch actuator to engage the clutch slower than usual, thus emulating the function of a conventional slipper clutch. Note that the unit only performs this function when using the downshift button; the rider can still use and operate the clutch and shift lever for downshifts (and upshifts) whenever and however he wants. The ShiftFX unit detects that the rider has manually pulled in the clutch and does not interfere with clutch control.

Likewise, it's when you have to pull away from a stop-or slip the clutch when making a particularly tight U-turn in a crowded parking lot-that the ShiftFX system sidesteps the shortcomings of every other two-wheel auto/manumatic transmission by retaining manual clutch control. In that respect, the ShiftFX is normal. It functions just like every other clutch-equipped motor-cycle you've ever ridden (unlike, for instance, Yamaha's YCC-S system on the FJR1300AE, which has difficulty maneuvering in tight spots due to the automatic clutch engaging neutral when you don't want it to). The rider-meaning you-remains in fundamental control, instead of forcing annoying adaptation to some sort of programming quirk that can leave you powerless at exactly the wrong time.

By allowing the rider to keep control of the clutch, ShiftFX actually manages to enhance both convenience and performance, rather than trampling the latter in the pursuit of the former. Instead of forcing you to become prisoner to electronic convenience and any idiosyncrasies that may come along with it, the ShiftFX system is there as an option to help if desired-not required. And that was the idea all along, according to Pick: "We wanted to give the rider more control-not less." Ultimately, Pick wants an OE motorcycle manufacturer to license his invention; and based on our experience with his well-designed system, it may be only a matter of time.-Charles Everitt

We Missed A Shift
In our hot-weather-gear buyer's guide ("Keep Your Cool," August '07) we had the images for the two Shift jackets mixed up. Shown here correctly are the Air Avenger ($199.95, avail-able in sizes S-XXL) and Airborne Mesh ($99.95, avail-able in sizes XS-L) jackets. For more information visit www.shiftracing.com or call (888) 744-3848. Our apologies to Shift; as punishment for the mistake, we made Kunitsugu commute for a full week in insulated cold-weather gear. Temperatures reached 105 degrees Fahrenheit.