Such was the impact of the first Ninja ZX-6R in 1995 that it contributed to a whole new class of motorcycle, the Supersport 600. Challenging the efforts of other manufacturers in the class, the Ninja ZX-6R was the first aluminium beam frame in its class. Pretty much straight away all other Japanese manufacturers accelerated development of true Supersport 600’s; but the Ninja from Kawasaki, is for many, the definitive mid-weight Supersport machine.

Now 25 years since the ZX-6R first wowed the motorcycle world with its incredible performance and power to weight ratio, here we take an affectionate look at a quarter of a century of innovation, racing success and engineering excellence.

But what was life like pre-6R?
Well – appropriately – Kawasaki were already big players on the mid-weight performance scene so it was natural that this experience would spawn the ZX-6R. First true sports model in this segment for Kawasaki was actually a member of the GPz family, the GPz550 of 1981.

Offering quite stunning performance the Kawasaki advertising of the time told a very accurate story, this was truly a “Red Revolution”. The first bright red air-cooled, four-cylinder GPz550 twin rear shock models made way for Uni-Trak suspended machines and – certainly in terms of four stroke motorcycles – the rule book about cubic capacity and performance was more or less torn up.

Then in 1985 – a full ten years before the first Ninja ZX-6R - the GPz600R appeared. Water-cooled with a 16 valve cylinder head and a perimeter style frame plus16 inch (40cm) front and rear wheels, the stunning GPz was for sure a “line in the sand” and an indication of things to come from Kawasaki.

The experience gained over those intervening years allowed Kawasaki engineers to dream of a logical next step, a true Supersport mid-weight machine with racetrack looks, race track handling and race track performance; and in 1995 the Ninja ZX-6R was unleased onto the world stage.

Re-writing the rules: Ninja style
Before the advent of the Ninja ZX-6R Kawasaki had already been creating Ninja machines but these were larger capacity machines such as the ZX-9R and the hugely popular ZXR750. Both machines were popular with riders but both were what might be called “full sized” machines, the ZX-6R offered something else.

Attractive to riders migrating up the capacity ladder and, in the fullness of time, for riders who wanted to “downsize”, the ZX-6R hit a “sweet spot” being big enough for riders of a wide range of heights and weights to feel comfortable on but not so physically large that the ZX-6R felt intimidating or unmanageable. A true “bike of the people”.

In performance terms the figures were astonishing with speed and acceleration figures achieved that were once the preserve of machines twice the cubic capacity plus precision handling achieved with minimal rider input or effort. No wonder then that Kawasaki hardly had the category to itself for long enough to take a breath before other manufacturers got in on the action.
 
With its innovative Kawasaki Ram-Air induction, weight of 182kg and acceleration of 0 to 97 km/h in 3.6 seconds, the first F model of ZX-6R lasted three years on the showroom floor before being replaced by the G model in 1998 which included such upgrades as an increase from 100PS to 108PS at peak power and an updated cowling design.

Following this was the J iteration in 2002 pushed the horsepower further still to 112PS and adopting a 180 section rear tyre along with the updated to twin headlamps in the cowling.

A big step change arrived in 2002 as the cubic capacity – but not the physical size – of the ZX-6R changed to 636cc, this engine size being “ideal” in terms of creating power and torque according to the Kawasaki engineers. Looks did not change aside from graphic treatments and, once more, the ZX-6R was praised by media and owners alike for its blistering performance and, thanks to the increase in engine size, commendable torque figures. For racers the capacity limit in many Supersport racing series was 599cc so Kawasaki did also offer the model in that “reduced” capacity for track riders.

Fans of innovation were rewarded the very next year as the ZX-6R moved to fuel injection in 2003 with the advent of the B1-H model. Radical and Radial were the watch words with Radical new styling and Radial mount six piston brakes came as standard fitment along with the adoption of an inverted front fork. Revving higher than any previous model, the machine transitioned to lightweight digital meters while the Ram-Air inlet was broadened and power increased slightly.

2005 heralded the debut of the C1 model with even more power at 130PS. The big news was in the styling with changes to the appearance of the frame and, for the first time, an under-seat exhaust system. With a generous, rounded appearance coupled to the 636cc capacity, the 2005 machine was rated by many as a great combination of astonishing performance coupled with a forgiving nature. The ZX-6R had come of age and was now able to be “all things to all riders”.

There was no doubt as to where the DNA of the ZX-6R ultimately lay and for 2007 anyone who thought Kawasaki would soften the mid-weight class King realised in no uncertain terms that Kawasaki wanted to remain in place on the throne.

With a new engine design and displacement for both road and track offerings at 599cc, the ZX-6R was launched at the Barber Motorsports complex in Alabama with the support of a number of notable Kawasaki racers including current crew chief to Jonathan Rea, Pere Riba as well as former 125cc Grand Prix rider Noboru “Nobby” Ueda, Shunji Yatsushiro who had ridden 500cc Grand Prix as well as Roger Hayden and the legend that is Akira Yanagawa. With a refocus on track usage, the frame, swing arm, suspension, brakes, and body were completely redesigned. The totally new engine featured a stacked gear arrangement in which the crankshaft, primary drive and countershaft are placed in a triangular format for a shorter, more compact power-plant. 

In 2010 the engine was further upgraded and the Assist and Slipper clutch made its first appearance. Now common on many Kawasaki road motorcycles, this clever device not only prevents rear wheel hop on downshifts but, by its arrangements springs and ramps, means it is far easier to operate with less hand strength required than a conventional cable operated clutch.

Again in 2013, the ZX-6R had a major overhaul effectively making it a brand new bike. Cylinder capacity once more reverted to 636 cc and there were two fuel maps available via a switch on the handlebars. Engine technical advances – and the 636cc capacity - meant the new version enjoyed increased torque and horsepower especially at lower RPM. On the rider aid side of things, Kawasaki TRaction Control (KTRC) with three modes (sport, rider and rain) appeared as standard equipment plus Kawasaki Intelligent anti-lock Brake System (KIBS) was available in many markets.

That brings us almost up to date with the last significant update in 2019 consisting of new gearing, changes to meet Euro4 requirements, the adoption of a KQS Quick Shifter for upshifts, updated bodywork , new LED headlights and an updated dashboard. For 2020 one last colour change and the ZX-6R bids a fond farewell as it does not feature in the 2021 Kawasaki range within Europe.

For 25 years the Ninja ZX-6R has dominated the mid-weight Supersport arena riding the crest of a wave of interest in ultra-high performance 600cc class machines. And as the market evolves so does Kawasaki’s offering with the advent of the Ninja 650 with a twin cylinder power-plant and trellis type chassis opening the mid-weight Ninja options even wider and to a greater number of riders. Now even a newbie can ride a mid-weight Ninja as their first sporting machine.  

After a full quarter of a century, the Ninja ZX-6R has garnered a cabinet full of trophies, numerous wins, fastest laps and championships on track plus a legion of hard core road riding devotees as well as fans new to the brand.

Always at the cutting edge and always willing to deliver the most thrilling and engaging of rides, the Ninja ZX-6R can be rightly recognised as being crucial to the development and success of the mid-weight Supersport class. Whatever the future holds, the Ninja ZX-6R can - and will - be regarded as a truly an iconic machine.
 
Quick facts
Ninja ZX-6R World Championship wins:
Andrew Pitt – 2001
Kenan Sofuoğlu - 2012, 2015, 2016
 
Supersport World Championship manufacturers title – points accrued by all Kawasaki riders in a championship season - 2013, 2015, 2016