When it comes to performance, no class is more competitive than middleweight sportbikes. To stand out in this crowd, a motorcycle needs to do everything better than well — it needs to kick serious tail in every department. Hats off to the Kawasaki Ninja® ZX™-6R then, winner of 600cc comparison tests in just about every publication and website of note on the planet. With an engine the critics agree feels bigger than 599cc, and a chassis that out handles all others, the ZX-6R returns as the bike to beat in 2010.

With a fine-tuned chassis including a class-exclusive Big Piston Fork and fully adjustable shock out back, razor-sharp handling sets the ZX-6R apart. To optimize front-rear rigidity balance, frame stiffness around the swingarm pivot and the rear engine mounts is carefully tuned, with the compact engine rotated forward around the output shaft for a steep cylinder bank angle and optimal center of gravity. An exhaust layout with a short side muffler keeps the weight low, and an exhaust pre-chamber further contributes to the ZX-6R’s mass centralization.

The Ninja ZX-6R’s lean physique is fundamental to its light handling, with every component on the bike carefully scrutinized for minimal weight. The intake resonator box and supports for the instrument panel and mirrors are unitized with the enlarged —to optimize intake volume — Ram Air duct, contributing to weight savings and improving rigidity. Camshafts are made of lightweight chrome-moly steel, and light, magnesium engine covers all add up to big weight savings, along with transmission, oil pump and starter gears carefully engineered for maximum strength and minimal weight.

Along with its light weight and compact design, the ZX-6R engine is packed with details to give it precise throttle control and amazing performance, particularly in the mid-range. Smooth power delivery is achieved through outstanding combustion efficiency. Cylindrical guides in the top of the airbox guide the fuel charge into the intake funnels to reduce buffeting and improve cylinder filling, along with advanced cylinder porting techniques. High-current secondaries in the ignition coils provide hot, consistent sparks at all rpm.

In addition to its more than healthy bottom-end torque and smooth throttle response, the engine’s mid-range performance benefits from a similar number of refinements, including double-bore velocity stacks with inlets at two different heights, special-profile pistons with low piston-ring tension for reduced friction, and advanced cam chain guides for excellent cam-chain stabilization.

That strong mid-range provides great drive out of corners and is harmonized with the engine’s silky smooth high-rpm performance. This linear throttle torque delivery results in unparalleled controllability and offers the rider precise throttle control at all rpm. This predictability pays dividends when making mid-corner power adjustments. When combined with the reduced need to downshift provided by its healthy mid-range performance, the predictable throttle response makes it easier for riders to maintain their rhythm when stringing corners together.

In keeping with its racing heritage, the ZX-6R employs a cassette-type transmission that simplifies gearing changes at the track, reducing set-up time and allowing more time for riding. A slipper clutch allows quick downshifts without upsetting the rest of the chassis when reducing speed on corner entry.

Corner-entry controllability is yet another ZX-6R strong suit, thanks to the use of Showa’s revolutionary BPF (Big Piston Front fork). The BPF utilizes a large-diameter internal piston, which permits a reduction in damping pressure, for smoother action and better front end feedback — especially under braking and initial corner turn-in. Additionally, the BPF eliminates many of the internal components used in a cartridge-type fork, simplifying construction and resulting in a lighter overall fork weight.

Having already designed a lighter and more rigid swingarm for the Ninja ZX-10R sportbike, the Kawasaki engineers utilized many of the same design components for the ZX-6R’s swingarm. Shared swingarm parts include both left and right inner plates, the left outer plate, rear stand bosses, brake caliper stopper, chain guard and swingarm pivot shaft.

The response from Kawasaki’s acclaimed triple petal disc brake package with radial calipers is as refined and powerful as ever. Radial-mounted four-piston calipers and 300mm petal rotors up front provide awesome power and excellent feel. The 220mm rear petal disc features a pedal coaxially mounted with the footpeg for increased mid-stroke braking efficiency and optimum feel. Its master cylinder reservoir mounts forward of the swingarm — freeing up space around the footpeg, reducing parts and contributing to weight savings. It all adds up to unflappable composure under braking, and helps provide the precise control and feel that allows Supersport racers to enter corners harder.

To better capitalize on this lighter machine and its precise control response, the rider interface is appropriately fine-tuned to enhance feedback from bike to rider and vice versa. The relationship of the seat-to-pegs-to-bar “rider triangle” places the handlebars close to the rider and angled for a highly intuitive riding position. The fuel tank cover is flared just so around its top edge, providing a large contact patch and contributing to excellent rider feedback — similar to the ZX-10R. A narrow rear sub-frame and seat leading edge provide a slim, highly flexible riding position for moving around the bike, as well as a shorter reach to the pavement.