When Kawasaki introduced the ZX-6R back in 1995, it was the first middleweight sport bike, since the 1992 GSXR600 with an aluminum frame. It had a dry weight of 401.2 lb (182.0 kg), wet weight of 454 lb (206 kg), and was capable of accelerating 0 to 60 mph (0 to 97 km/h) in only 3.6 seconds.
1997 Kawasaki Ninja ZX-6R
With competition from Honda's CBR600F4i, Suzuki's GSX-R600, and Yamaha's YZF-R6 getting more aggressive, Kawasaki decided to make an unusual move for the 2003 model year. They increased the capacity of the traditional 600 cc (37 cu in) motor to 636 cc (38.8 cu in). For riders who needed bikes for displacement-restricted racing, Kawasaki also made available a limited production 599 cc (36.6 cu in) version called the Ninja ZX-6RR, but the 636 cubic centimetres (38.8 cu in) ZX-6R would be their main mass production middleweight sport bike.
2002 Kawasaki Ninja ZX-6RIn 2003, there were a number of changes to the ZX-6R, or ZX636 as it is often referred. The engine was now fuel injected and engine speed was raised around 500 rpm which resulted in a slight gain in power. Radial-mounted four-piston brakes replaced the previous six-piston brakes and the front forks were now inverted. Chassis improvements resulted in higher rigidity and less weight. An all digital instrument panel was also introduced and a larger ram air inlet moved to the center over the headlight, running through the headstock. The bike carried over to the 2004 model year with just color scheme changes. The ZX-6RR won the Supersport category award for Masterbike 2004 and placed third overall. MSRP for the 2003/2004 models was US$7999.
2005 Kawasaki Ninja ZX-6R
In 2005, Kawasaki again revamped the ZX-6R. Engine speed increased again by 1000 rpm resulting in 113 hp (84 kW) at 12250 rpm. The frame and swingarm were updated, but the main changes from its predecessor lay in the design. The aluminum frame was now painted flat black, fairings were more round, and integrated turn signals were used (euro model). The exhaust was now centrally under the seat (a configuration commonly referred to as an undertail exhaust). Most of these changes were mirrored in the 599 cc ZX-6RR. For the second year in a row, the ZX-6RR again won the Supersport category award for Masterbike 2005 and placed 3rd overall. The bike carried over to the 2006 model year with minor suspension changes and new color schemes. The 2005 and 2006 ZX-6Rs had an increased MSRP of $8,699 USD.
2007 Kawasaki Ninja ZX-6R
After four years of offering their 636 cc ZX-6R for street use and an entirely separate 599 cc ZX-6RR for displacement-restricted racing classes, Kawasaki offers only one ZX-6R for 2007, and it displaces 599 cc. Previous years of the ZX-6R's engines were all built from the same basic design, but the all-new engine for 2007 was redesigned from the crankcase up. In following with what their competitors had already been doing, Kawasaki's new engine features a stacked gear arrangement in which the crankshaft, primary drive and countershaft are placed in a triangular format for a shorter, more compact powerplant. It's now about 40 mm smaller in both length and width, said to yield greater cornering clearance. By using a former 125 cc Grand Prix racer as the ZX-6R’s chief development rider, Tomomi Manako, Kawasaki claims a focus has been put on track usage. Frame, swingarm, suspension, brakes, and body are completely redesigned and the bike shares very few parts from the previous model. MSRP was increased to $8,999 USD and the ZX-6R was carried over to the 2008 model year with just color scheme changes.
For 2009, Kawasaki dramatically changed the appearance of the ZX-6R to match the more angular look of the ZX-10R. The frame was lightened albeit with the same basic construction resulting in 191 kg (420 lb) wet as opposed to 205 kg (450 lb) in 2008. Kawasaki claims the new ZX-6R is 10 kg lighter than the previous model. The greatest changes for 2009 were the redesign of the exhaust, now carried low and not requiring the thick under-seat construction of 2008 and especially the introduction of the BPF (Big Piston Fork) suspension from SHOWA for a more progressive brake-dive. The 2010 ZX-6R is changing once more with an improved engine and slipper clutch. The exhaust pre-chamber has more space and also limits exhaust noise giving the rider a smoother ride. New double bore intake funnels features 2 available heights which gives performance upgrades in both high and low rpms. The front seat is now lower which makes reaching the pavement much easier.
