Sportbike development continues to astound as horsepower to dry weight specs have now surpassed the once mythical 1:1 ratio. But pure horsepower is meaningless if it can’t be controlled. To that end, Kawasaki has redrawn its litre-class ZX-10R with a next generation engine management system that literally decides the most efficient amount of power needed to turn the quickest lap time. Bertrand Gahel explains.
When will it stop? Whether you’re a hardcore sport rider, a cruiser type or even a motojournalist, you have asked the question at some point and wondered when sportbikes will finally hit a horsepower and performance level humans just can’t cope with anymore. If Kawasaki’s new-for-08 Ninja ZX-10R is any indication, then the answer is a resounding, never.
But how can it be, how can average riders, not just Rossi-like freaks of nature deal with sub-400-pound (180-kilogram) motorcycles generating horsepower numbers rapidly closing in on the 200 mark? What about five or 10 years from now when that mark edges toward 250 hp and dry weight figures keep dropping?
As with all forms of high calibre racing—Grand Prix, MotoGP, Formula 1, Superbike, etc.—the solution for production bikes lies in electronics: computer-assisted riding, no less. Motorcyclists have already experienced such outside help from ABS, from the occasional anti-wheel spin system or even from semi-automatic transmissions such as the one in Yamaha’s FJR1300AE, but Kawasaki brings that concept to another level in the 2008 ZX-10R with a feature it calls KIMS.
KIMS, which stands for Kawasaki Ignition Management System, is so new to production motorcycles there’s a good chance you’ll actually read a whole lot of nonsense about it. Already in Doha, Qatar, where Kawasaki held the 10R world introduction on the magnificent Losail circuit, there was rumour of KIMS being some kind of disguised traction control. Some riders even claimed they “felt it” come into action at some corner exit.
Be that as it may, Kawasaki insists that KIMS is not traction control “because it doesn’t monitor wheel speed.” Since traction control doesn’t actually need wheel speed monitoring, the comment was interpreted by many as a way of hiding what was thought to be the system’s real function—controlling rear-wheel spin under acceleration—further fueling the aforementioned rumour.
I simply pulled project leader Yasuhisa Okabe aside and asked. According to Okabe San, while “KIMS could possibly be modified with a race kit to act differently,” on the stock ZX-10R, it is not a traction control system. It can, however, stop wheel spin in very specific circumstances, namely if it feels a sudden spike in revs—hence sudden wheel-spin—at constant or very slowly opening throttle. It can then act on any of a large number of parameters to limit power. But it will not monitor and control wheel spin at corner exits, nor will it prevent a high side or interfere if a rider spins the back coming out of a turn. So what does KIMS do, then?
MANY ANSWERS CAME FROM LAPS AROUND LOSAIL ON THE ZX-10R
FIRST, I can confirm KIMS isn’t traction control. I know because I rode the new 10R off the track, onto the grass and easily spun the back wheel in all gears. But it is only after noticing how quickly I got comfortable with this new 186-hp bike (Canadian and US ZX-10Rs will be limited to 179 hp) on this very technical new track that that I really started to grasp the purpose of KIMS and how the system works. Particularly astounding to me was how accessible and downright friendly the ZX-10R felt coming out of the long track’s second hairpin. While that kind of low speed/high lean corner followed by a relatively long, straight and fast section of the track should have been particularly challenging on such a high horsepower, high torque bike, I was able to just smoothly roll the throttle right to its stop and let the 10R gracefully catapult me to the next corner. It all seemed so easy it almost felt like the 10R was underpowered under about 6,000 rpm, and amazingly accessible from there to redline. Thing is, words like friendly and accessible just shouldn’t be in one’s vocabulary while describing a bike of such high calibre.
These words, however, didn’t prevent the ZX-10R from displaying majestic off-corner acceleration and carrying massive speed down the fast parts of the track, qualities that not only confirmed the new model’s powerhouse status, but also its very unusual “super fast yet super rider-friendly” nature.
Discussing that nature further with Kawasaki engineers not only shed some more light on KIMS, but also gave me an insight to things to come regarding these rapidly evolving sportbikes. The fact is, big horsepower becomes a problem when it reaches certain levels by making traction difficult to manage, by overstressing tires and chassis and by intimidating the rider. If the net result of a given model’s evolution must be quicker lap times, then big power can be downright counterproductive. This is why even experienced testers often turn faster lap times on smaller displacement models and climb off litre-bikes shaking their heads in awe of the experience. KIMS is Kawasaki’s answer to that phenomenon.
It is a next generation engine/ignition/power/torque management system that literally decides the most efficient amount of power needed to turn the quickest lap time. It reduces or limits torque and horsepower in delicate situations like corner exits, making it easy for the rider to trust the machine instead of fearing it, then gradually gives back the engine’s full potential in less critical situations such as fast sections. The end result is a chassis that isn’t unnecessarily upset, a throttle that’s fully opened sooner at corner exits, and that also stays fully opened during a bigger portion of the circuit length. All of which basically describes the recipe for fast lap times, the new ZX-10R’s primary goal.
Of course, in order to reach that goal, much more is required than a sophisticated engine management system, namely a good chassis. The 2008 ZX-10R also excels in that regard by proving both flickable and stable (some occasional and minor headshake would be the only exception) at the same time as offering wonderful manners while trail braking hard at corner entries. Braking itself is very strong and communicative, but the initial bite is kind of soft. However, I felt that the bike’s stopping characteristics actually made my confidence go up yet another notch because I could get hard on the brakes without fear of any sudden reaction.
Actually, it seems every part of the riding experience offered by Kawasaki’s latest ZX-10R evolution is specifically intended to take the drama out of riding a powerful 1000cc sportbike. Taken together, the compact and purposeful riding position perfectly suited for track riding, the powerful yet compliant engine and the extremely precise, communicative chassis form an unbelievably accessible and efficient package around a racetrack.
The new ZX-10R allows riders to accomplish something they rarely, if ever, are able to do on models of this class: get comfortable, get confident, actually think while riding and get to work on the little things that ultimately make lap times fall. Considering that you sometimes get off these bikes feeling as though you were in a rodeo, I’d call that quite an accomplishment. As opposed to making you question when all this will stop, the technical aspects of the ZX-10R make you wonder how long we’ll have to wait for models capable of true superbike-like 190-200 rear-wheel horsepower.
by Bertrand Gahel