The Mach III engine that powered the Kawasaki H1 500 is one of the best motorcycle engines ever made.
In the ’60s’Kawasaki was known for reliable small-displacement twins, but aspired for more sales and higher profits that larger displacement motorcycles provided. They produced the W1, a copy of the BSA A10 Rocket but it quickly became a dated model when it had to compete with Suzuki’s T500 and Honda’s innovative CB450.
Three cylinders meant there was more exhaust port area, which translates to more power in the two-stroke world. At 8,000rpm the 498cc MAch III pumped out 60bhp and had a top speed of 115mph (185kpm). The cylinders had large cooling fans to prevent overheating, the clutch and gearbox were light and the 120 degree crankshaft ran smooth.
When you design with one goal in mind, as Kawasaki did, other areas of the bike suffer. The frame and forks were tiny so the handling was terrible. It was not uncommon for riders to feel the frame flex during high speeds. The tires were thin, provided no grip when wet and the brakes were inadequate and didn’t grip when wet either. It was dangerous even for a motorcycle and it soon became known as the “Widowmaker”.
The Mach III engine pelted the H1 down the quarter mile in under 13 seconds surpassing 100mph. The completely stock H1 was faster than any other mass produced bike on the planet regardless of engine size. If you owned one you were going to win and if you raced, the size of your cojones determined your place.
The H1 was obviously a success, Kawasaki’s first big hit and it quickly became a cult motorcycle. Eventually Kawasaki bowed to consumer groups boycotting it for safety reasons. Later models were outfitted with disc brakes, a steering dampers and aesthetic changes until the final model (the 1976 KH500) saw an actual reduction in horsepower.
The original H1 would not be allowed on the roads today but its development led to Kawasaki’s infamous ‘Z’ models.
