The 1973 Kawasaki Z-1 represented Kawasaki's effort to keep up with Honda.

Kawasaki had made its mark in the U.S. with its fast but frightening two-stroke triples, but Honda's success with its more civilized CB750 Four did not go unnoticed.

The market was beginning to lean away from two-strokes in general, and Kawasaki wanted to maintain its performance image while offering a more roadable four-stroke machine.

Introduced in 1973, the Z-1 boasted a 903-cc double-overhead-cam inline four that significantly upped the performance ante. That engine soon became the benchmark other companies would aim to beat, and it proved to be a bulletproof design that continued as a dominant force in racing circles for years.

In contrast to the strong-running powerplant, however, the chassis of the Z-1 was notoriously unstable. Several aftermarket manufacturers quickly devised more competent frame designs that could be filled with Z-1 power.

No color options were offered for the U.S. market: All Z-1s were painted brown with orange accents. Not considered a particularly appealing combination at the time, many early Z-1s received custom paint treatments shortly after leaving the showroom.

Keep reading for more pictures of the 1973 Kawasaki Z-1 motorcycle.

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