As most our regular readers know, we like to fuel your and our collective love of motor culture with vehicles that are exciting, interesting and sometimes just different.
The Kawasaki H1 Mach III may be one of the better two-wheeled examples that embodies all of those attributes.
In the mid 60s, the United States became the largest motorcycle market in the world. Relative to other countries that sometimes preferred lighter, more agile bikes, American riders of the time wanted their motorcycles to have a ton of horsepower. They wanted to win the stop-light drag race. They wanted straight-up speed.
Honda had already introduced the wildly successful CB450 four-stroke in 1965. Kawasaki had its own four stroke in the W2 650, but that wasn't getting it done in the U.S. market. They knew they needed something different. In 1967, they initiated the N100 project. The goal of the project was to produce a motor with 500 cc displacement that was capable of 60 hp and 13 second quarter-mile times.
By 1966, the N100 program was well underway. They started with two distinct approaches. The first utilized their existing 350 cc parallel twin two-stroke that had been simply bored out to 500 cc. The two cylinder approach allowed Kawasaki to maintain the rotary valve intake, which was capable of producing more horsepower than a conventional piston port or read valve intake at the time. The second approach was to develop an entirely new engine with an inline three cylinder two stroke engine. It wouldn’t be able to utilize the rotary valve of the twin. Despite that, Kawasaki knew there was a unique character to the triple concept.
When they learned that Honda was working on what would become the CB750, that cemented the decision - Kawasaki decided that the three cylinder was more distinctive, innovative, and frankly more exotic looking, so they decided to move forward with it. The new engine utilized prominent cooling fins, and a capacitor discharge ignition (CDI), which utilized thyristors and other mechanisms to increase ignition voltage tremendously, thus improving the efficiency of fuel burn.
With the triple cylinder engine platform, Kawasaki had accomplished it's goals. When the bike debuted, it produced 60 hp at 8000 rpm, and had a standing quarter-mile time of under 12.8 seconds. That was more horsepower than the Manx Norton and Seely Grand Prix bikes of the same year. And that was without any tuning, jetting, or exhaust work. There was clearly more power to be had without too much effort for those willing to tinker. Several motorcycle publications have referred to the Kawasaki H1 triple engine as one of the 10 best engines ever made in motorcycling. In the first year of its public availability, Motorcyclist magazine said the H1 engine was the best "ever produced in a motorcycle meant to sell to anyone who has the money to purchase it".
Despite housing this groundbreaking engine, the H1 was far from flawless. Many saw the gearbox configuration as odd, with neutral at the bottom of the pattern, below first gear. The brakes were not very strong, or as predictable as other motorcycles of the day. And then there was the handling. At best, nobody will ever praise the handling of the H1. Most would suggest that the chassis just wasn't up to the task handed it by the decidedly quick, peaky engine. Perhaps one of the journalists of the time described it best when he wrote, "The engine writes checks that the chassis and handling cannot cash”. Even as late as 1975, the model’s last year, Cycle Guide said, ‘It’s still the fastest in a straight line, but can’t turn worth a damn’.
The bike was fairly light for the time, at 385 pounds, with 57% of that pressing on the rear tire. With a power curve that hit hard around 5500 rpm, it caught many riders off-guard when the front tire would reach skyward. The H1 quickly earned the moniker of the widow maker. In a strange way, the brutally fast but ill-handling motorcycle captured the rebellious, eclectic spirit of many people of the time. People embraced it, despite all its issues. Maybe even because of them. The H1 was a hit for kawasaki.
When the H1 debuted, it retailed for $999. Anyone with $1000 could do the quarter-mile in under 13 seconds at over 100 mph, and ultimately top out around 125 mph. It was an incredible bang for the buck. For perspective, the Harley Davidson XLCH of the same year was $1,698. Even the Honda CB750, which debuted in 1969 as well, retailed for $1495. And while the Honda made slightly more hp than the H1, it was much heavier, and therefore not as quick.
The H1 received minor mechanical and cosmetic modifications over the years. By 1972, the CDI ignition was replaced with a battery ignition system, and the bike received a much-needed front disc brake as well as a steering damper. That year, Kawasaki also unveiled the H2 - a wholly new bike - a 750 cc two-stroke triple design making 75 hp, and with a chassis better equipped for the job.
By 1976, Kawasaki had redesignated the H1 model. It was now called the KH 500. They had refined out many of the handling issues, and reduced the horsepower to 52, thus taking away much of the character and thrill of the bike to many. But for all intents and purposes, it didn't much matter. The two-stroke was becoming less plausible. So the two-stroke had largely been replaced by the four stroke - even within Kawasaki in that same year, by the four-stroke four-cylinder Z500/550
The Kawasaki triple was, and continues to be, a popular motor for drag racing with its available, albeit peaky power. It's racing success was not limited to the drag strip, however. In 1970, Ginger Molloy finished second behind Giacomo Agostini's MV Agusta for the 500cc World Championship.
In the spirit of full disclosure, I may be carrying some bias here. I own an H1 with chambered exhaust and drag bars. Over the years, I have owned several distinctive motorcycles, and ridden many more. Nothing sounds even close to, or evokes a visceral response like the H1. I cannot imagine the day I would ever part with my H1. Very few other bikes seem to stir as much conversation, or evoke the level of reaction as the H1 when I arrive at a destination. I have probably started more conversations with strangers, and made more friends as a result of riding the Kawasaki around than any other motorcycle I've ridden. It engages people. And that’s a big part of what it’s all about.