Which motorcycle did Kawasaki launch in 1972 as its 903 cc flagship, known internationally as the Z1?

Kawasaki launched the 903 cc Kawasaki 900 Super Four in 1972 as its flagship motorcycle, and it became widely known as the Z1.

The Z1 was Kawasaki’s answer to the Honda CB750. Its air-cooled, double-overhead-camshaft inline-four engine produced substantially more displacement than Honda’s 736 cc engine, helping establish Kawasaki as a major superbike manufacturer.

The motorcycle was sold under the 900 Super Four name in several markets, while “Z1” became the shorthand most enthusiasts use today. Later versions included the Z1A and Z1B, with detail changes such as revised colors and equipment.

The Z1 is sometimes confused with the later Kawasaki KZ900. The KZ900 was closely related, but Kawasaki introduced that model after the original Z1 series and used different market naming.