On March 13-15, 1973, Kawasaki rolled its Z1 900 onto Daytona International Speedway’s banked track to prove the new model’s performance and durability. Pumping out 81 horsepower and 54.2 lb-ft of torque, the grand-daddy of all Zs had the first part covered. However, Team Green billed the Z1 as a “touring” bike, so the air-cooled, four-stroke, DOHC, 903cc inline-four didn't just need to be powerful, it also needed to go the distance.

To illustrate the Z’s sporty and sensible sides, the manufacturer turned to Yoshimura to prep three race-ready units and Canadian racer Yvon Duhamel to lead the charge. As all speed and endurance attempts go, not everything went to plan, but the team achieved utter success despite the odds.

During the 1973 24-Hour World Record at Daytona, the Z1 900 set a new AMA closed course one-lap record of 160.199 mph. The squad also squashed world records with a 10-kilometer (6.2 miles) absolute speed of 150.845 mph and a 100-kilometer (62.1 miles) speed record of 141.439 mph.

In all, the Z set 52 World and American records, breaking all U.S. 300- to 2,500-mile speed records and all 2- to 24-hour speed records. Of course, the one that mattered most, the World 24-hour speed endurance record, proved that the Z1 could go faster, further, and longer with a total of 2,630.4 miles at 109.602 mph.

Some may dismiss the record-setting runs as a product of their time, but some manufacturers are still hanging their hats on endurance. As Kawasaki celebrates the 50th anniversary of the Z series, the vintage documentary puts the historic range in perspective.

Today, the neo-retro based on the Z1, the Z900RS, generates over 100 horsepower and backs that up with 72.3 lb-ft of torque. The Z range has come a long way in those 50 years, but that didn’t stop Kawasaki from honoring the impact of the Z1 900 with a limited 50th Anniversary Z900RS trim. The Z1 will always be a legend, and Kawasaki is ensuring that legacy lives on for another half-century.

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