Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/128372
Kawa§aki ZX-6R MOTOR KEY FEATURES: • Slipper clutch • 636cc (cheater) motor • Secondary shower-style fuel injectors in oval throttle bodies • Under-seat exhaust The ZX-6R is the bigger of the two motors in the company's middleweight range. (They also make the 599cc ZX-6RR for racing homologation.) The motor received major updates for 2005, including the secondary showertype fuel injectors similar to the units on the Honda. The new throttle bodies are oval 38mm units, which allow 20 percent more airflow than before without increasing the space the unit takes up in between the frame rails. The engine is a brand-new mill for 'OS and also includes a new cylinder head with larger intake and exhaust valves, new cam profiles, new pistons, a new crankshaft and rods. Additionally, there is a servo-actuated exhaust valve just upstream from the silencer to alter back pressure and midrange engine response. So how does it all work? Quite well actually, but testers commented that they expected more midrange punch than it offers and that it felt like it revved slow. It may suffer from the same syndrome that the Honda does: The top-end performance is stunning, but the midrange response isn't quite as accessible as on last year's model. Testers commented that the fuel-injection response was excellent both on and off of the track, with excellent response from a closed throttle. Most of the testers commented on the fact that the new 6R motor vibrates much more than the other bikes. There is always a bit of buzz detectable through the bars and pegs. One thing that all of our testers were really fond of is the new slipper clutch. The ZX-6RR had it last year, but this is the first year for the 636. Every modern sportbike should have one; it makes riding on the track so much more confidence inspiring. At the Streets, getting into the fast chicane at the end of the back straight is one of the keys to a fast lap, and the slipper clutch kept the bike settled there. The 6R turned the fourth-fastest lap at the track (a I:26.86), but we don't think it was the motor that held it back. The most likely culprit is that the more stabilityoriented chassis struggled getting through some of the tighter corners. CHASSIS/HANDLING KEY FEATURES: • Fully adjustable Showa 41mm inverted fork • Fully adjustable Showa shock • Braced swingarm • New frame • Petal-style brake rotors The ZX-6R is a brand-new bike from the ground up for 2005, and after riding the bike in Spain in December, we declared it a serious challenger for this shootout. One of the first things that is noticeable on the 6R is that it isn't as nimble as some of the other bikes in the comparison. A lot of this has to do with fact that the bike's rake isn't as radical on the new bike (25 degrees instead of 24.5) and it has more trail (106.68mm instead of 95) than the previous generation 6R. But what it loses in flickability it gains in midcorner stability. "I don't like the new Kawasaki as much as last year's bike on the track," Montano said. "The big thing for me was the fact that it feels so big. It really hauls butt, but the reciprocating mass from the engine and the large feel rubbed me the wrong way. It just doesn't turn as good as the three bikes ahead of it on my list." The frame was redesigned in an effort to lengthen the swingarm and decrease the distance between the steering head and the swingarm pivot. The new ZX-6R is rock solid, especially through some of the faster corners and through the fast chicane. The suspension on the 6R is excellent. The fork provides good damping rates and isn't nearly as harsh as some of the previous models' units. The primary reason is that the company made an unprecedented move and switched from its usual Kayaba units to Showa units both front and rear. That's a big deal, but the company was serious about improving the suspension, and the Showa stuff was beller. The action is smooth and predictable without any noticeable chatter. The shock is much the same with good damping. Combine this with the slipper clutch, and setting up for the corner during downshifts is a breeze. The Kawasaki turned the fourth-fastest lap time (a I:26.86), which has a lot to do with gelling the bike turned into some of the track's tighter corners. A more momentum-oriented track or a track with faster corners would play into the hands of the 6R much better. The brakes on the 6R were rated highly both on the ; 10~~01h~ @ ~ : 1$,200 rpm : ·_ . ._·-r-.. --·f.. .. 10 12 14 16 track and on the street by all of our testers. The calipers were already radial mounted, but the rotors are now a petal style similar to the units on the ZX-l OR. On the street, the ZX-6R is a good compromise between stability and quick turn-in. It doesn't turn as quickly as some of the others on a really tight road, but it is very rewarding everywhere else. Positives - Slipper clutch - Excellent mKlcomer stability - Excellent top-end performance - Awesome brakes - Good suspension Negatives - Buzzy engme - Feels big - Slower steering than before - LCD tach is hard to read CYCLE NEWS. APRIL 6,2005 19