There have possibly been more significant models than the Z1 that Kawasaki unleashed on an unsuspecting world in 1972… but very few, and arguably none more influential. That first 903cc superbike blew all rivals off the road, and introduced the dohc four-cylinder engine format that still dominates 50 years later.
Of this year’s Anniversary models it’s the Z900RS, with its replica design featuring a new ‘Fireball’ candy-colour paint finish, that reflects the original Z1’s shape and style. The first Zed confirmed Kawasaki’s arrival as a major manufacturer, and established a reputation for performance and reliability that has served the firm well ever since.
As the highlights of five decades of Zed power confirm, that naked, 903cc Z1 also founded a spectacular two-wheeled dynasty. The Zed family grew to incorporate larger- and smaller-capacity fours plus cruisers, shaft-drive tourers, forced-induction models and even a six.
1972 Original Z1: Well-cooked steak
Kawasaki pulled the covers off the Z1 at the Cologne Show in September 1972, but the key to its design and performance had come four years earlier. Honda had unveiled the CB750 at the 1968 Tokyo Show, trumping its rival’s prototype 750cc four, codenamed N600, which was almost ready for release. Kawasaki abandoned the 750, and went back to work to create a bigger, stronger and more powerful four.
The twin-cam layout added to the air-cooled unit’s performance advantage, and Kawasaki’s robust bottom-end would become equally important. Its reliability was partly due to a thorough testing program. The engine development team under Ben Inamura went through a series of prototypes, with codenames including New York Steak.
That American name was no coincidence, because the Z1 was created primarily for the