Kawasaki Ninja ZX-6R - Middleweight Motorcycles

The prototypical middleweight.

Kawasaki Ninja ZX-6R

Middleweight Motorcycles: Kawasaki Ninja ZX-6R

Over the past 25 years, 600cc, liquid-cooled, inline-Four supersport bikes have dominated the mid-displacement street category in Cycle World’s Annual Ten Best Bikes awards. Prior to our

selecting the Ducati 848 Streetfighter this year, the only other departures from the norm have been a V-Twin Honda Hawk GT taking the honors in 1988 and the three-cylinder Triumph Daytona 675 bucking the trend in 2006.

Looking back also reveals the success of Kawasaki ZX-6 and ZX-6R supersports. All told, the 600-class Ninja has amassed seven Ten Best awards to date. And since its 2009 introduction, the current-generation ZX-6R has strung together an unprecedented (within the category) three-year run at the top before being “displaced” under our newly redefined middleweight criteria.

Nevertheless, the 599cc ZX-6R still remains one of our favorites among traditional supersports. It tips the CW scale at just under 400 pounds without fuel, and on our dyno, it produces linear power from bottom revs to its 14,000-rpm peak output. Its torque curve is one of the flattest in its category regardless of engine configuration. The lower half of the rev range is devoid of bothersome dips or lulls, making the slick-shifting mill one of the more pleasurable middleweights when ridden in town. And at freeway speeds, it gives off only the slightest trace of engine vibration.

Despite its more civil side, this is a machine designed to win roadracing championships. You’re quickly reminded of its track-bred pedigree as the tach needle sweeps into the 8000-16,000 rpm green zone and the flow of power starts pulling your arms harder. The chassis also delivers precise, track-focused handling with an excellent level of feedback, stability and agility that all works in concert to bolster a rider’s cornering confidence. The Showa Big Piston Fork offers top-shelf damping control, and the Nissin brake system provides superb power and feel.

These fine qualities explain why it has taken an expansion of the middleweight category to knock the 2012 ZX-6R from the top step on our Ten Best podium. But Kawasaki already has an answer with the return of the 636cc ZX-6R, which was originally produced between 2003 and 2006. The notable boost in low-end and midrange power the super-sized 600 produces gives it a performance edge over its peers. It steps outside the rules of organized middleweight competition, of course, but those extra ccs give it great acclaim in the realm of real-world street use.


• Racer persona and performance with good street manners

• Killer top-end and midrange power

• Most affordable 600 supersport


• Drag holeshot requires ear/clutch-wrenching revs

• Four years old and due for an update

• Time for a new 636?

Dry weight:|398 lb.
Wheelbase:|55.1 in.
Seat height:|32.7 in.
Fuel mileage:|40 mpg
0-60 mph:|3.1 sec.
1/4-mile:|10.89 sec. @ 129.26 mph
Top speed:|159 mph
Horsepower:|109.3 hp @ 14,010 rpm
Torque:|43.9 ft.-lb. @ 11,870 rpm