The Kawasaki GPZ900R (also known as the ZX900A or Ninja 900) is a motorcycle that was manufactured by Kawasaki from 1984 to 2003. It is the first member of the Ninja family of sport bikes. The 1984 GPZ900R (or ZX900A-1) was a revolutionary design that became the immediate predecessor of the modern-day sport bike. Developed in secret over six years, it was Kawasaki's and the world's first 16-valve liquid-cooled inline four-cylinder motorcycle engine.