The 636cc ZX-6R’s primary advantage is from 7000 rpm to 11,500 rpm, which is precisely where the tach needle rests when riding down the freeway or at city street speeds. Something tells us that’s hardly a coincidence.
The 636’s gauge cluster is a bit busier with the addition of KTRC and ride modes, but still easy to read at a glance. Typical Kawasaki mirrors provide a clear, unimpeded view of who’s in tow.
Showa’s Separate Function Big Piston fork has preload adjustment in the left leg and damping adjustment in the right leg. Springs are .50N/mm softer and provide an unparalleled level of comfort over rough patches of road. The Nissin monobloc brake calipers deserve equal praise, and offer great power through the pull but no overly aggressive initial bite.
Shock spring is 7.5N/mm lighter and equally as centered on comfort as the front end.
The 2004 ZX-6R was hard motorcycle to fault, and that bike’s success has clearly influenced Kawasaki’s decision to return to a 636 platform for 2013.
Kawasaki's Kenan Sufuoglu won four World Supersport races in 2012 and finished the season atop the points standings. This in itself is hardly news, as Sufuoglu and Kawasaki have separately proven strong contenders in any series. What's interesting though is that Sufuoglu's success last year came on a bike that Team Green will not ship to the U.S. in 2013 — the 600cc ZX-6R, which will be offered overseas as a 2013 model. The U.S. market instead gets access to Kawasaki's new 636cc ZX-6R, a bike that the manufacturer has built with the everyday rider in mind.
Sport Rider is no stranger to the new ZX-6R platform; we first threw a leg over the 2013 model during the bike's world launch last October, and then touched on its many new features in our first ride report ("Born Again," January '13). Once the dust settled on the ZX-6R's big intro, however, we found ourselves still curious as to how the bike would handle daily commutes, and how it would work on roads that weren't bowling-alley smooth. On top of that, we wondered how the street-biased 636 would work at the track when there wasn't a flock of Kawasaki technicians attending to every last detail, including suspension setup. All of these were questions that warranted some more one-on-one time with the bike.
Our interest in spending added time with the new ZX-6R was coupled by a desire to expose the bigger differences between the 2013 model and last year's 599cc model. Aspirations in mind, we decided to throw a leg over not one, but two ZX-6Rs as part of this test; every inch of tarmac that we'd cover on the 636, we'd cover on its smaller-displacement sibling. This wasn't a chance to pick a winner between the two bikes, mind you, rather an opportunity to see if Kawasaki's change in pace had legitimately sent the manufacturer in the right direction. And if it had, how far had Kawasaki propelled itself into the green?
Don't judge a book by...well you know the rest
Kawasaki is quick to remind the industry that its 2013 ZX-6R is centered on around-town comfort, but its spec sheet suggests that the bike will still ignite your senses by way of clear-cut performance. The suspension, brakes and engine have all been updated, for instance, and Kawasaki's only sweetened the pot by outfitting the 636 with its three-level traction control system and separate power modes.
The ZX-6R's engine is the most reworked and benefits from a 2.6mm-longer stroke in addition to a slew of internal changes, including reshaped ports, cams and pistons. The 636 pumped out 111.2 horsepower at 13,300 rpm and 46.3 foot-pounds of torque at 10,900 rpm when strapped to our SuperFlow dyno. Our 2012 test mule, by comparison, spun the drum to the tune of 110.4 horsepower at 14,000 rpm and 44.5 foot-pounds of torque at 11,400 rpm. What's more impressive than the incrementally higher peak power figures is that the 636 holds its advantage across the entire rev range, and that the biggest gains are found between 7000 rpm and 11,500 rpm, precisely where you'll find the tach needle when riding at a safe and legal speed.
Roll-on testing further confirmed the ZX-6R's midrange advantage; the 2013 ZX-6R went from 60-80 mph in just 3.13 seconds and 80-100 mph in 2.91 seconds. Compare that to our 2012 test model, which covered the former gap in 3.64 seconds and the latter in an elongated 3.49 seconds.
The 2013 ZX-6R's ergonomics remain track-focused, but a relaxed reach to properly positioned clip-ons means 60-mile-plus commutes aren't succeeded by ten minutes of "ice on, ice off" wrist therapy. That same level of comfort doesn't trickle down through the rider triangle, and we found the footrest-to-seat distance to be insufficient for any rider over the six-foot mark. Fortunately, a slightly cramped seating position is among the only downfalls to the Ninja's otherwise stellar ergonomics package. Typical Kawasaki mirrors provide a clear, unimpeded view of who's in tow.
The newer ZX-6R's aggressively shaped fairings further blur your understanding of the bike's design brief, but a few miles spent in the saddle remind you of its street-biased nature. Biggest difference this year is that both the clutch and brake lever have a lighter pull and consequently require less forearm manipulation. Feel through the clutch lever's travel is silky smooth as well, which works in conjunction with the torque-happy engine to provide effortless stoplight-to-stoplight launches.
The 2013 model's suspension package is developed around .50N/mm lighter fork springs and a 7.5N/mm lighter shock spring that further boost around-town performance. The setup absorbs potholes, manholes and speed bumps with a plushness that would otherwise have had us believing the 2012 bike was suspended by wood slats. The benefits don't culminate at the freeway onramp either; the newer ZX-6R coasts down the interstate with few wrinkles in the chassis and absolutely no buzz through the handlebar. Frankly, our test riders could only wish to have had the same comments regarding the 2012 ZX-6R.
The 636 engine is no powerhouse up top and starts gasping for air well before you run into the rev limiter, but that increase in midrange power that was highlighted by our back-to-back dyno runs proved advantageous through every last section of canyon road that we covered. Last year's ZX-6R isn't a poor performer through any part of the rev range mind you, but the 599cc engine shines brighter once the tach needle skips past the 13,000 rpm mark — pass that point on the street, however, and chances are you'll almost immediately be seeing flashing red/blue lights in your mirrors. The 636, in comparison, happily grunts off the corner almost regardless of where the needle resides, and continues to drive through the midrange in a way that allows you to forgo the shift lever in the tight stuff.
The 2013 model's modestly damped Showa Separate Function Big Piston fork and rear shock surprisingly don't reach their limits any quicker than an experienced rider would, and provide such a high level of feedback that they were extremely easy to set up at the track — even without Kawi techs on hand, mind you. The 636's 5mm-shorter wheelbase combines with a .5-degree steeper rake to make the bike much lighter through a right-left transition, and the only area where the newer ZX-6R steers slower is at the entrance of the corner. Presumably, the latter characteristic is a result the bike being buried in the lower part of its travel as a result of the softer, aforementioned springs.
Corner entrances aren't by any means a tiresome experience on the 636, and the F.C.C. clutch manages to keep the bike stable under aggressive braking. "The slipper clutch works really well," claims Kento, who goes on to say that, "I think Kawasaki's done a good job of tuning the fuel injection under deceleration, which helps as well." The Nissin brakes deserve equal praise, and are far superior to the two-piece units on the 2012 model. Biggest difference is that the monobloc pieces have a less aggressive initial bite, but plenty of power through the pull. Last year's calipers, in contrast, are much more difficult to modulate and are just a finger twitch away from upsetting the chassis. Even at a tight track like the Streets of Willow, there was absolutely zero brake fade to speak of when riding the 2013 model.
The 600's engine initially feels stronger at the racetrack (and its top-end performance would likely hold benefits on a track with longer straights), but it becomes readily apparent that the more lively sensation is a result of its more aggressive power delivery than an actual power advantage. The 636 feels less frantic on the gas; it's a little like a matured honor-roll student in comparison to the ADD-distressed teenager that the 2012 bike resembles. What's more, the 636's added midrange allows you to drive through the middle of the corner without wrapping the throttle to the stop (in search of revs) and testing adhesion limits.
Rear tire grip is rarely ever a concern aboard the 636, but when the tire does start to slide, Kawasaki's traction control system quickly steps in. The KTRC system works so well in fact, that we never saw any reason to toggle to the Off position at the track. And we're not too proud to admit that in colder conditions and on wet mornings, we gladly set the system to Level 3 while simultaneously toggling over to the bike's Low power mode; both settings provided a level of control that our right hand simply couldn't.
The Bigger Picture
It'd be easy to assume that the laptime-motivated 2012 ZX-6R would outshine the 2013 model when ridden aggressively. And the 600 does indeed feel like it could shatter a few more lap records than the 636 in the hands of a racer, but the disparity between the two bikes when ridden at anything less than a World Supersport-winning pace is far too large to ignore. The 636 is a less demanding bike to ride, and beyond that it's a more comfortable bike to ride on a daily basis. Put simply, it's proof that you don't have to sacrifice comfort and enjoyment for outright performance.
So has Kawasaki's bold change in pace resulted in a better package? Absolutely.
The newer ZX-6R coasts down the interstate with few wrinkles in the chassis and absolutely no buzz through the handlebar
|Test Notes 2013 Kawasaki ZX-6R|
|+||Bike is less physically demanding to ride|
|+||Smooth power delivery matches plush suspension|
|+||Brakes are less intimidating, but still powerful|
|–||Power tapers off quickly up top|
|–||Steering on the brakes feels heavy|
|x||Kawasaki took a chance on its 636 platform, and it's paid off!|
|Suggested Suspension Settings|
|Front: Spring preload — 7 turns in from full soft; rebound damping — 4 turns out from full stiff; compression damping — 5.5 turns out from full stiff; ride height — 8mm showing above top triple clamp|
|Rear: Spring preload — 6mm thread showing; rebound damping — 1 turn out from full stiff; compression damping — 1.25 turns out from full stiff|
Kawasaki's Original "Cheater" Bike
Riding the 2004 ZX-6R
Between 2003 and 2006 Kawasaki sold a 636cc ZX-6R alongside a purpose-built, 600cc ZX-6RR that was offered more for race homologation purposes than anything. And while the 636 lasted just four years on showroom floors (Kawasaki ultimately decided to refocus its energy on the 600cc model), it managed to gain a cult-like following that's difficult to overlook. "A lot of the pre-orders we've had for the new ZX-6R are actually from guys that owned one of the original 636s," says Kawasaki's Brad Puetz. "These guys just love that bike." After throwing a leg over the mostly stock '04 ZX-6R belonging to Sam Ho of Rosemead, California, we can't blame them; Kawasaki definitely hit the nail on the head in its first go at a "cheater" bike.
The '04's engine feels midrange-biased, and especially stout from 8000 to 10,000 rpm, but at the same time the bike's not completely opposed to higher revs. Unlike the newer ZX-6R, it also feels more partial to an aggressive riding style; suspension is on the stiff side for instance, plus the brakes and chassis (despite being almost ten years old) act as though they'd be right at home on the track. That's the big difference between the '04 and '13 model though: Kawasaki designed the original 636 knowing that it would eventually end up competing in one race class or another (and it did, with great success). Kawasaki designed the '13 model, on the other hand, knowing that racing is no longer a priority for most motorcycle enthusiasts.
The bikes' different design briefs have resulted in a pair of 636's that are undoubtedly common in certain ways, but also very different. And despite those differences, you can't help but think that the first-generation's success had at least some influence on Kawasaki's decision to return to a 636 platform for 2013. It's a good model, clearly, and with advances like traction control and ride modes, we wouldn't be surprised to see the new bike stick around for a bit longer than Kawi's original "cheater" bike.
Avon 3D Ultra Supersport Tires
Avon's new 3D Ultra tires were levered onto our 2012 and 2013 Kawasaki ZX-6R test mules for the track portion of our test, and were subsequently tested on the street. More specifically, we spooned onto each bike a set of 3D Ultra Supersport tires, which are constructed from a softer compound than Avon's 3D Ultra Sport tire and marketed as a street/track tire. Compared to the track-specific Xtreme, the Supersport features more grooves for better performance in myriad conditions.
Avon's 3D Ultra lineup of tires share multiple technologies, including a 3D siping that uses interlocking three-dimensional points in thin grooves to limit carcass flex and enhance warm-up capabilities. The Supersport tires also make use of Avon's Advanced Variable Belt Density (A-VBD) and Reactive Footprint (RF) technology, which combine to provide better stability when the bike is vertical and a larger contact patch when the bike is leaned over. What's more, the tires are constructed with Avon's Front Groove technology, which is intended to prevent uneven front tire wear over the course of the rubber's lifespan.
The Supersport tires in particular proved plenty capable at the track and especially proficient through the entrance of the corner, a trait we attribute to the tires' quick steering characteristics and compliance on the brakes. The rear tire is equally as admirable and offered enough performance to get us through a full day of aggressive riding. We'll say, however, that the tires' soft carcass was immediately apparent and allowed the tires to get hot after an elongated on-track session. Smaller slides at the exit of the corner weren't exactly a rarity by the end of a 20-minute stint.
The Supersport tires performed well around town as a result of that soft carcass, and absorbed bumps masterfully on LA's finest roadways. Warm-up time was plenty quick during even the coldest of mornings, and while tire wear at the track wasn't overly impressive, we feel that the Supersports provide an adequate balance between track and street performance.
Avon 3D Ultra Supersport fronts are available in two size options and retail for $182.33 to $197.08. Rear tires are available in four size options and retail for $255.09 to $297.01. For more info on sizing and a list of retailers, log onto www.avonmoto.com.
|2013 Kawasaki ZX-6R|
|Type: Liquid-cooled, transverse inline four|
|Valve arrangement: DOHC, 4 valves/cyl. Shim-under-bucket adjustment|
|Bore x stroke: 67.0 x 45.1mm|
|Compression ratio: 12.9:1|
|Induction: Keihin EFI with 1 injector/cyl., 38mm throttle bodies|
|Front suspension: 41mm Showa SFF-BP inverted fork with adjustable preload, compression and rebound damping, 4.7 in. travel|
|Rear suspension: Single Showa shock absorber with adjustable spring preload, compression and rebound damping, 5.3 in. travel|
|Front brake: Dual 310mm rotors with dual radial-mount four-piston Nissin monobloc calipers|
|Rear brake: Single 220mm rotor with single-piston Nissin caliper|
|Front wheel: 3.50 x 17 in., cast aluminum alloy|
|Rear wheel: 5.50 x 17 in., cast aluminum alloy|
|Front tire: 120/70ZR-17 Bridgestone Battlax S20F|
|Rear tire: 180/55ZR-17 Bridgestone Battlax S20R|
|Rake/trail: 23.5 deg./ 4.0 in. (102mm)|
|Wheelbase: 54.9 in. (1395mm)|
|Seat height: 32.7 in. (830mm)|
|Fuel capacity: 4.5 gal. (17L)|
|Weight: 422 lb. (191 kg) wet; 395 lb. (179 kg) dry|
|Quarter-mile: 10.61 sec. @ 132.83 mph|
|Roll-ons: 60 – 80 mph/ 3.13 sec.; 80 – 100 mph/ 2.91 sec.|
|Fuel consumption: 36 – 41 mpg, 38 mpg avg.|
It would have been embarrassing if our back-to-back rides on the 2012 and 2013 ZX-6Rs rekindled our love for the old bike more than they ignited a passion for the new model, but fortunately that wasn't the case. Our appreciation for the newer Ninja has nothing to do with its evocative press kit or shiny new fairings either; the 2013 636 is simply a better bike.
The larger 6R's performance in all stages of this test still came as somewhat of a surprise; we've continually described the 636 as street-biased and subdued. Kawasaki hasn't undermined the middleweight's track potential however, and I actually enjoyed my laps aboard the 2013 model more so than I did my laps aboard the 2012 model. The 636 feels less frantic; brakes, for instance, are less in your face but with still plenty of power, suspension is more comfortable but plenty apt for aggressive riding, steering is lighter through transitions and the smoother power delivery makes corner exits less of a white-knuckled experience.
Traction control and riding modes only add to the bike's potential (both proved beneficial on rain-influenced rides), and convince me that Kawasaki's change in pace was worthwhile.
I'll admit I was a bit apprehensive after hearing that Kawasaki had designed the new 636 more towards the street rider. Of course the engine was going to have better power, but what about the chassis and suspension?
Bradley's comments on the 2013 ZX-6R after his experience at the press launch calmed my nerves a bit, but his time on the street at the launch was fairly limited. Was this bike really going to be that much better?
The first quarter-mile up one of our favorite twisty road test venues and I had my answer. The new ZX-6R simply does everything better on the street, from a smoother ride to a much more enjoyable powerband. And yet once I got the opportunity to ride it at the racetrack, I found it doesn't give away everything there in exchange for that improved performance on the street. It's actually easier to ride on the racetrack than its predecessor. Major kudos to Team Green for taking the initiative with the new ZX-6R.
And the progress moves forward… While the 2012 ZX-6R is a great machine, the 2013 ZX-6R is even better. It's definitely built for what seems like the customer in mind more than just the racetrack. The 600 is a great bike don't get me wrong, but compared to the 636, it feels as if it's hopped up on Red Bull 24/7. It's a hard, edgy, aggressive feeling bike, as where the 636 feels more like a nice smooth Pepsi. Just go with the flow; you want to ride to work? No problem. You want to hit the track? You're covered there too! It's the perfect double-threat machine. Kawasaki, what took you so long?