In the late 1960s, if you wanted the quickest stoplight-to-stoplight bike on the block, there was a clear choice: the 1969 Kawasaki 500 H1 Mach III. This air-cooled, three-cylinder, two-stroke easily outperformed the heavy four-strokes of the day.
What made it so special?
Riders instantly fell in love with the machine’s performance. Kawasaki claimed a top speed of 118 mph with 12.2-second quarter-mile times, which was astonishing performance at the time.
With a claimed 60 horsepower, weighing in at 383 pounds dry and a five-speed transmission, the Mach III had lightning-quick acceleration. But the frame and suspension weren’t quite up to the task. That, coupled with drum brakes, made spirited riding quite entertaining.
The heart of the Mach III was its air-cooled, 499cc, two-stroke engine. Six main bearings and six small flywheels designed to reduce vibration necessitated a long crankshaft and extra-wide cases. The three cylinders were inclined forward slightly, and each cylinder breathed through its own 28mm Mikuni carburetor.
The Mach III also featured the first electronic ignition system on a mass-production motorcycle. As with any new design, it met with mixed success. Spark plug wear was reduced and cold-weather starts were fast and easy. Electrical short-circuits reportedly led to a few damaging fires, though.
But with that powerful engine and $995 price tag it was easy to overlook the bike’s flaws, making the Mach III a desirable machine.