ZX-10R
By 2004 Kawasaki had realized that there was no way to re-invent the ZX-9R as a liter bike king. So it tossed the 900 Ninja in the crusher and came up with an all-new bike. Taking cues from the short-lived ZX-12R Ninja (the monocoque-style frame) and the ZX-636R (bodywork), the 10R was the new Ninja and quickly earned a fearsome reputation.
Like all the other Ninjas before it, Kawasaki had given the ZX-10R a real fire-breathing motor, and with a screaming top end and savage throttle response it gave nothing away to the opposition in terms of pure HP.
The chassis was a different matter though. While it worked well enough on smooth racetracks, on the road it was a handful. Together with the crazy motor, the 10R made going fast more difficult for most riders than Suzuki's GSX-R or Yamaha's R1.
Updates for 2006 and 2008 refined the engine and handling package, and although the 2008 model suffered from snatchy fuel injection an unheralded remap for 2009 has made the latest liter-sized Ninja much easier to live with.
ZX-12R
1999 saw the biggest Ninja yet: the ZX-12R. Suzuki's Hayabusa and Honda's Blackbird had both trampled on Kawasaki's reputation for the fastest bikes, and the big K was pissed. The result was a pretty fearsome-looking machine, but with a rather confused character. Some parts of the 12R were pure track-biased: riding position, minimal passenger accommodation, firm suspension. But the sheer size and weight of the bike made it a challenge on the track.
The motor was deranged: 170 HP on the dyno and even more when the ram air intakes were snorting cool 150 mph air. It was quite revvy though - making a smaller 1,199cc engine produce the same power as a 1,299cc Hayabusa meant the Kawasaki had to rev higher.
So while the 12R handled a little better than the Hayabusa it still couldn't keep up with a proper supersport bike, while the harder edge of the Kawasaki made it less easy to live with. For two-up touring or long distance work, the Hayabusa's extra comfort and more flexible engine made it the better choice.
Finally, Kawasaki had bowed to political concerns late on in the development process and cut the top speed on the ZX-12R Ninja from its 200 mph design target back to around 185 mph - so it wasn't any faster than a Hayabusa.
ZX-14
It wasn't until 2006 that Kawasaki finally got the Hayabusa off its back with the ZX-14. Unlike the ZX-12R, there was no pretense at supersport handling or track ability: the ZX-14 was a pure hyperbike with the comfort, tank range and road manners to suit. The 1352cc engine had the balls to take on and defeat the Hayabusa, with more power, more torque and smoother delivery. Brakes and suspension were a step ahead of the Hayabusa, and together with a modern digital dash and sleek bodywork, the ZX-14 is a fitting flagship model for the mighty Ninja family.