2008 Kawasaki ZX-10R Preview
Spin Control: a pre-ride inspection
When some moto journalists called the new ZX-10R's ignition management system Traction Control, corporate lawyers bounced off their rev limiters. After the engineers and marketers had argued their case, they were allowed to describe it as a device to minimize wheelspin coming off the corners. Maybe we should call it "Spin Control!"
Kawasaki is launching an all-new ZX-10R in Qatar as this story is posted. Ed-in-Cheese Duke is there to ride it, and he’ll post his report in just a few days from now. But before boarding the plane we were privy to a private, in-depth technical briefing from Kawasaki's Rob Taylor. The material we saw was so sensitive that we had to go to their head office to see it; the PowerPoint presentation wasn't allowed out of the building. Taylor is KMC-USA's supervisor of curriculum development–he's the guy who will train Kawasaki techs on the new bike and he gave us more background on the bike than anyone outside the company has seen to date. Here's the inside story...
The bike's a Kawasaki, after all, so it's appropriate to begin with a description of the motor. Kawasaki's philosophy is to make the motor–the "air pump"–as efficient as possible and then to figure out a way, using engine management and exhaust technology, to meet emissions standards. We'll structure this report along those lines, too; we'll begin our virtual tour by going in the inlet tract, then through the motor and out the exhaust port, then we'll deal with the transmission, engine peripherals and that controversial ECU. Last but not least, we'll touch on changes to chassis, bodywork, and the rider interface.
On the intake side, the ram-air inlet is smaller and longer. Holes have been cut between the passage and the frame spars, which serve as harmonic dampers of intake noise. The air filter is smaller but higher-flow, and the airbox is lined with sound-damping foam. The 43mm throttle body intakes are now oval, with slash-cut inlets to take maximum advantage of air currents and pressure differentials within the airbox. The oval shape obviously helps keep engine width to a minimum, but also allows a denser air charge with a more laminar flow in the center of the port, as opposed to around the perimeter.
The primary fuel-injection nozzles now pump through two larger-diameter holes. The secondary nozzles are 10-hole jobs, with activation based on rpm and data from the throttle-position sensor. Secondary butterflies are active above 7,000 rpm.
Improvements to the intake side of the motor typically are felt more in torque, while tuning the exhaust side is felt more in horsepower. The intake port volume is larger, to give it more midrange torque. Kawasaki formerly hand-polished every inlet port, but that procedure is now automated.
"This bike has never been down on top-end power," Taylor told us, in a monstrous understatement. That's why most of the engine changes are intended to boost mid-range power and tractability. The intake valves are now Ti, they're 8.1 grams lighter. Their size is the same, 30mm.
The camshafts and valve timing are completely different. On the intake side, lift's been increased by 0.6mm. The intake valve stays open longer to take advantage of the ram-air effect. Camshaft lubrication's been revised, with a larger main feed and more holes. This change was not made only to address a wear-and-tear issue; a weak lubrication system and an inconsistent oil film changes pressure and friction in the system–the net effect can alter cam timing by up to two degrees.
The lubrication system in the head has been revised; the oil channels are now in the head instead of the cam cap. This makes the cam cap more rigid, and makes cam timing more precise. Previously, flex in this part of the valve assembly could account for a significant timing shift, most noticeable with high-lift cams at high rpm.
The engine has an all-new cylinder head, with reshaped combustion chambers–the impetus here was mostly to improve heat dissipation and meet emissions standards. Heat was an issue because, as Taylor told us, "We can't give you figures, but it has a ton more horsepower and torque–especially torque–with lots more midrange."
We weren't given any information about the pistons or rods, so we assume any changes to those components are slight. There's a major change in the bottom end, however: The crankshaft is 2.2 pounds lighter. To change weight but maintain inertia, Kawasaki changed the shape of the crank webs, moving mass further from the axis of rotation. This should not change the crank's overall gyro effect that much–and definitely isn't anything you should ever feel on the street–but Kawasaki claims the motor will spin up faster at low rpm and have more crank momentum (and presumably gyro effect at high rpm.)
On the exhaust side, lift remains unchanged but valves open later, to use more combustion energy, again for more torque. The exhaust valves are slightly smaller, as is exhaust port volume, for improved scavenging and, again, mid-range power. It should be cleaner and crisper off idle. The valves are 1mm smaller and slightly lighter.
The transmission now features a ratchet-style shift mechanism–as seen on the KX dirt bikes–as opposed to a pawl, which is designed to be able to withstand a little more abusive shifting. Ratios are lower in 1st, 4th, and 5th gears – a change made to allow the ratios to take advantage of the revised crankshaft – and an additional tooth on the rear equates to a 2.5% reduction in the final-drive ratio.
The fuel pump is now fully contained within the fuel tank, as it is on the ZX-6R, instead of protruding down into the airbox. This keeps it cooler (and facilitates an increase in airbox capacity, to 2.2 gallons.)
"Alright, already!" we hear you muttering towards your monitor, "what about the traction control?"
"This is the area we need to be careful," begins Taylor. "The language used on this slide was just approved by legal… they gave us a 'bye' up to this point, they're not going to go after Cycle World to retract it or anything, but you can't refer to it as traction control."
So, like Voldemort in Harry Potter, it can't be named. It will hereinafter be referred to by its acronym KIMS–for 'Kawasaki Ignition Management System'. The company's legal minders insist that it is a system intended for use under closed-course/racing conditions "where experienced racers often experience [undesirable] wheel-spin exiting corners."
As you've probably already read in our '08 Kawasaki Preview article the new ZX-10's engine computer constantly compares rpm to data from the gear position and speed sensors. If engine speed suddenly spikes, the system checks clutch and throttle positions to determine whether the wheel-spin is the result of a rider-controlled slide or an accident in the making. In the latter case, engine power is decreased by retarding the ignition timing and reducing fuel flow until wheel-speed and engine speed are brought back into line.
Whatever KIMS is, it's definitely not a "GP-style" traction control system, nor does it offer launch or wheelie control. Riders who whack open the throttle in mid corner will, in fact, make the system "think" their action is intentional (since it is not active when the throttle is wide open.) If the power figures intimated in our briefing are anything like accurate, a ham-handed rider can still expect a highside so severe he'll face FAA charges of failing to file a flight plan.
A race kit ECU will be made available, but it's not known at this time whether the KIMS feature will be programmable or even present. Although pretty much all the MotoGP and SBK TC systems rely on front and rear wheel-speed sensors, the engine-speed system is race proven, according to Kawasaki (and there are many people who feel it's been proven for years by Yoshimura Suzuki in the AMA.)
One thing KIMS does is reduce the flow of unburned fuel through the catalyzers under certain conditions, and Kawasaki's legal department is eager to emphasize that point, too. Apparently, running too much raw gas through the cats can cause them to stop, uh, catalyzing. If you'll pardon the pun, the cat's out of the bag, but they'd like us to believe the system's main objective is adding a day of life to your smog certificate.
"What we're trying to do is optimize grip and acceleration, let's just leave it at that," says Taylor. But then he goes on to elaborate, "Say you're riding through a corner and you're just feathering the throttle, sliding intentionally, the system won't cut in, but if you rub up the tire and it starts to spin, it's going to cut in [pause for effect] to protect the catalyzer. As far as we're concerned, there's no highside protection, there's not a rider on the bike and there are no attorneys in the grandstands."
Those precious catalyzers are now a pair of hundred-cell units that flow a little better than the previous 200-cell version. After the cats, there's a prechamber under the motor, which is strictly a noise-control feature and an "orthogonal" muffler with a Ti sleeve. As on other Kawasakis, there's an exhaust butterfly valve in the system, which is another noise control feature (it closes at high rpm.) Kawasaki claims that it's located far enough down the system that, although racers are quick to take it off, "You can't even see it on the dyno."
American units will not have oxygen sensors, but European models will have them, to conform to Euro 3 regulations.
More power from the motor inevitably means more heat to disperse, so the radiator is narrower but taller, for a net cooling improvement of 0.9 kilowatts. The new ring fan is smaller and quieter. The water pump is now the same one seen on the ZX-14. It causes less cavitation, which results in more efficient cooling, particularly in the cylinder head area (at the top of the system, where gas bubble collect.) Kawasaki cites a cooling rate increase equivalent to an additional 20 liters/minute.
The all-new frame is assembled of "pressed convex parts," welded together. The new manufacturing process was intended provide "massive feedback" to the rider. The head pipe is 10mm further forward and 20mm longer, for more rigidity in the front end and better feel. Rake angle has been increased 1 degree to 25.5 degrees, and trail is increased 8mm to 110mm.
At the other end, the swingarm pivot area is reinforced, and the swingarm itself is all new, 2mm longer, with the stabilizer bar relocated from below the main arm to above it. The net result of all geometry changes is that the wheelbase is 25mm longer.
The most interesting part of the frame is an area in the middle of the spars, about between the rider's knees, where a tube bridges both sides of each frame spar. Kawasaki test riders felt the increased stiffness here, in the form of a crisper steering response. The outside elements of the main frame spars were slightly dished before, and they are now slightly convex, so that there's increased contact with the rider's outside leg while hanging off in the corners. This is where the massive feedback will presumably come from. The new, minimalist rear subframe is attached differently, to better transmit loads to the suspension.
The bike is suspended by a 43mm Kayaba fork up front. Fork travel is 4.7 inches, with "diamond-like coating" that reduces stiction. The springs are now bottom-mounted and tolerances have been tightened between the internal diameter of the winding and the cartridge. The effect of this is that, near maximum compression of the springs, the windings act as a secondary, progressive damper as the fork oil flows past the windings. Clever, the folks at Kayaba, eh?
At the rear, the remote-reservoir Kayaba shock has separate high- and low-speed compression damping and is adjustable for ride height.
At the heart of the new front brake system, you'll see new, four-piston Tokico radial calipers. Both pistons on the previous unit were 32mm in diameter, but each new caliper has one 32 mm piston and one 30 mm piston. This, according to Kawasaki, was for increased feel at the lever–especially at the point of initial bite. Despite the slightly smaller piston cross-section, braking efficiency is marginally higher. The pads are now dual units and grip 310mm discs that are 0.5 mm thinner. They have 10 mounting pins (up from seven) for increased heat transfer. The rear brake is unchanged.
The wheels are now squeeze-cast and stronger. The front hoop is actually slightly heavier, with more lateral rigidity (there's more material in the spokes) while the rear is lighter. American ZX-10Rs will come with Bridgestone Battlax BT016 tires, while Europeans will get Pirellis. Fronts are 120/70, rears 190/55.
In the cockpit area, the windscreen is lower and the "chin dent" in the fuel tank is deeper, allowing a more aerodynamic position in a full tuck. (You can bet that taller screens will be popular, even with many racers. No one spends that much time with their chin actually on the tank.) The tach has funky new look, with a green "happy zone" from 6,000 to 12,500 rpm. The nominal redline is unchanged, at 13,000 rpm. Only the brave hit the rev limiter on a bike like this anyway! The shift light is programmable. The LCD displays have now been UV protected and the whole display is adjustable for brightness. So, "I couldn't see my speedometer" won't be a viable excuse any more.
Looks are subjective, but the revised mirrors and front turn signals are noteworthy. The new tailsection is slick. The license plate holder, signals and mirrors are all easily removable for track days. Another bodywork feature is the barely perceptible lip on the trailing edge of the fairing. It's not a spoiler, but functions as a boundary generator to deflect laminar flow around the rider.
We'll know more after riding the ZX-10 in Qatar, and will be posting a riding impression soon. Until then, it's interesting food for thought that Kawasaki's 'spin control' system opens a new door for streetbike riders. It may prove to be one of the most important safety features ever built into a motorcycle–especially for ordinary street riders. But don’t call it traction control.
This isn't the fault of Kawasaki's engineers, who have obviously tried hard to give us the most powerful–and rideable–bike in its class. Nor is it the fault of Kawasaki's marketing department, who couldn't have been blamed for identifying KIMS as the lead story for this launch. It's simply down to lawyers whose job it is to protect Kawasaki from guys who might ride like idiots, and then sue the company for making a product that couldn't completely protect them from themselves.
Ah well, this whiff of frustration will soon be blown away by the windblast of a wild ride around Qatar's Losail circuit. Stay tuned.