The Kawasaki Ninja ZX-10R is a motorcycle in the Ninja sport bike series from the Japanese manufacturer Kawasaki, the successor to the Ninja ZX-9R. It was originally released in 2004 and has been updated and revised throughout the years. It combines an ultra-narrow chassis, low weight, and radial brakes. In 2004 and 2005 the ZX-10R won Best Superbike from Cycle World magazine, and the international Masterbike competition. Components Engine Kawasaki engineers used a stacked design for a liquid-cooled, inline four-cylinder engine. The crankshaft axis, input shaft, and output shaft of the Ninja ZX-10R engine are positioned in a triangular layout to reduce engine length, while the high-speed generator is placed behind the cylinder bank to reduce engine width. With a bore and stroke of , the ZX-10R engine's one-piece cylinder, and crankcase assembly reduces weight and increases rigidity. The DOHC are machined from Chromoly steel, built for strength; four valves per cylinder improve high-rpm breathing; and the forged, lightweight pistons offer high heat resistance to further enhance the bike's power-to-weight ratio. Cooling system In addition to liquid cooling, the ZX-10R engine has an oil cooler adjacent to the oil filter to reduce oil temperatures. Slosh analysis was also used to design the internal structure of the oil pan, thereby reducing windage losses and helping to maintain low oil temperatures. Clutch A multi-plate wet slipper clutch transfers power to a six-speed, close-ratio transmission ideal for closed-course competition. The back-torque limiter automatically disengages the clutch (partially) under hard downshifting at high engine speeds to prevent rear-wheel hop during corner entry. Wheels A new six-spoke wheel design is claimed to be almost as light as special purpose race wheels. Since the 2006 model, the sidewall profile of the rear tire has been increased from 190/50/ZR17 to 190/55/ZR17. History 2004–2005 The 2004 model was the debut of the Ninja ZX-10R with minor updates in 2005. It was compact, and with a chassis rivaling those of a 600cc sportbike and with a short wheelbase and a high power-to-weight ratio, which helped the handling. The exhaust system was fully titanium with a single muffler. 2006–2007 Among other changes, the 2006 model had twin underseat exhausts which contributed to a increase in dry weight. The engine remained largely unchanged. 2008 The ZX-10R was all new for its launch for the 2008 model year. There was a dramatic change in appearance with the bike with a much more