1970 Kawasaki H1 Mach III
By Margie Siegal
Kawasaki H1 motorcycles are revered today as the fastest, most powerful and most out-of-control motorcycle of its day. This is Tony Silveira’s 1970 Kawasaki H1 Mach III.
Photo by Nick Cedar
1970 Kawasaki H1 Mach III
Years produced: 1969-1975
Claimed power: 60hp @ 8,000rpm
Top speed: 119.14mph (period test)
Engine type: 498cc 2-stroke air-cooled transversely-mounted inline triple
Weight (dry): 410lb (186kg)
Price then: $995 (1970)
Price now: $3,500-$7,000
Tony Silveira started his love affair with motorcycles early, but unlike many motorcycle-crazy kids, he rode his bikes, even fast two-strokes, carefully.
In fact, Tony still has the Suzuki Hustler he bought in high school back in the day — and with only two nicks showing on the original tank. That Hustler is now part of his collection of classic Japanese motorcycles, which includes two early Kawasaki H1 motorcycles, revered today as the fastest, most powerful and most out-of-control motorcycle of its day.
Building up to the Kawasaki H1
Kawasaki Heavy Industries really entered the motorcycle business in 1960, when it bought a controlling interest in Meguro, one of Japan’s first motorcycle companies. Meguro was subsequently combined with Meihatsu (a Kawasaki subsidiary that had been building small motorcycles since the mid-1950s), producing Meguro and Kawasaki-badged machines.
In 1965, Kawasaki tried exporting the 650cc W1, a BSA look-alike originally developed by Meguro in the 1950s. Unfortunately, the W1 was considerably slower than the BSA A7 it had copied, and given a choice between the fast and familiar BSA and a slower Kawasaki of unknown reliability, most riders chose the BSA.
Kawasaki management was quick to appreciate that in America, speed sold bikes, so they designed the 250cc Samurai A1 for the U.S. market. A fast two-stroke, it did well from its introduction in 1967 and was soon followed by a 350cc version.
By this time, the Honda CB450 Black Bomber was being marketed and the Suzuki Titan T500 was for sale. Clearly, there was a market for mid-size bikes from Japan, but Kawasaki wasn’t interested in marketing just another motorcycle. Kawasaki wanted to make a splash, and had the resources from its ship and bridge building operations to fund the research and development necessary to build a truly newsworthy two wheeler.
With engineering assistance from Osaka University, a new effort code named the “N100 Plan” went forward. The goal was a motorcycle with 500cc displacement developing 60hp and able to lay down 13-second quarter-mile times, then considered over the achievable limit for a road bike.
Two different two-stroke engines were considered: a larger version of the Samurai twin and a triple. Eventually, Kawasaki decided on the triple since three small cylinders and pistons were easier to keep cool than two large cylinders and pistons. The triple was also lighter than the twin, as the smaller individual power impulses allowed Kawasaki engineers to shave weight off the transmission and clutch.
The triple used a metering pump to deliver oil to the main bearings and state of the art CDI electronic ignition for spark. Large piston ports metered air/fuel mix to the combustion chambers, and the mufflers were really expansion chambers, normally found only at the racetrack.
In the Sixties, triples were exotic. “When this bike came out,” Tony remembers, “my best friend’s older brother bought one. I was 14 or 15 and I knew it was too powerful for me. It was scary just listening to him start it up. The sound was memorable.” The brother managed to ride the bike for two years without crashing it before he sold it — a remarkable achievement. “That bike intrigued me from the beginning. The bikes I knew about had two or four cylinders. Three mufflers was oddball,” Tony adds.
The three-cylinder Kawasaki H1 Mach III appeared in the spring of 1969. Simply styled with a blue and white tank, a bench seat and thin fenders, its performance was electrifying. “Hottest Production Bike Yet” blared Cycle’s April 1969 cover. In the accompanying article, “Blue Streak,” editor Gordon Jennings noted, “With 60 horsepower and a dry weight of 400 pounds, it’s entirely possible that the new Kawasaki 3 is the fastest production motorcycle ever put in the hands of an unsuspecting public.” Cycle recorded a standing-start quarter mile of 12.8 seconds and 0-60mph in four seconds. Kawasaki had made its splash.
A little racing on the side
A bike this fast naturally found its way to the racetrack. The speedy 500 did well at the drag strip from the start, but Kawasaki wanted road racing trophies as well. Unfortunately, getting the H1 to handle and convincing its not-quite-debugged electrical system to behave at speed for the length of a road race proved problematic.
Four H1s turned up at Daytona barely a month after the bike showed up in dealers’ showrooms. They did not do well, due mostly to the usual mechanical and electrical problems that surface when you run a bike at sustained speed on a race track for the first time.
To help put the new bike on course, Mr. Hatta and Yukio Otsuki (Kawasaki’s frame and engine gurus, respectively) joined talents to improve the handling and reliability of the H1 race bike. A prototype H1R first appeared at the 1969 Sears Point National, ridden by flat tracker Dave Smith. Smith put the fastest laps on the track that day, but handling problems dogged him as the rear wheel displayed a tendency to lose traction and slide around during hard acceleration out of corners. Adding to troubles, the rectifier mount broke during the race and the engine started misfiring; the win went to a slower, but more reliable, Suzuki.
In 1970, Kawasaki offered 40 replicas of the Sears Point bike — with a different frame — to aspiring road racers. The new frame was an adaptation of the 1969 250cc racer chassis with rubber washers between the engine mounts and the frame tubes to dampen vibration, and a longer swingarm to fix the traction problem. Jess Thomas, who test rode the new H1R in early 1970 for Cycle, noted, “The workmanship and finish on the bikes is absolutely first rate. Usually, when one buys a racer, the first thing he does is look for the components that are obviously going to fall off on the first lap. The only things that looked questionable on the whole bike are the battery mount, the rectifier and regulator mounts, and two right side expansion chamber mounts.”
Kawasaki’s two-strokes remained winless in National racing until 1971, when they hired a French Canadian named Yvon DuHamel. DuHamel, who had made a name for himself racing 250 and 350 Yamahas, turned out to be one of the few racers who could keep the two-stroke Kawasakis on their wheels and headed in the right direction. DuHamel earned five National victories for Team Green between 1971 and 1973.
H1 road machines for 1970
Meanwhile, the road machines were evolving. To differentiate it from the white and blue 1969 model, the 1970 version of the H1 sported a red tank with white stripes and red side covers with “Mach III 500” emblems. A perforated grille between the CDI boxes and the seat eliminated a potential hot spot under the rider. As on 1969 bikes, the gas tanks featured impressions for decals accentuating the Kawasaki name: Later H1 tanks were smooth.
The 1970 H1 was every bit the road burner the 1969 machines were. In a Cycle Guide test published in September 1970, a stock H1 just out of the crate turned a 13.10-second quarter mile. A few weeks and a few hundred miles later, the same bike was running 12.72 in the quarter mile. In a display of honesty rare at the time, the magazine pointed out that some owners were getting bad CDI boxes, resulting in rough idling. Otherwise, the magazine announced that the handling problems demonstrated by the 1969 bikes had somehow been cured — with a caveat: “A great deal of care must be exercised when moving away from a stop light, because once the RPM reaches 4,000 to 4,500, if too much exuberance is displayed by the rider, it will break the tire loose instantly ... ”
That level of ferociousness wasn’t to last, however, as Kawasaki started taming the beast in 1971, detuning the engine, stiffening the frame and altering the weight balance to make it easier to ride. A disc brake replaced the twin-leading-shoe front drum brake in 1972, and other “improvements” were made over the next few years, most aimed at making the H1 more rideable. The 500cc triple went out of production in 1975, a victim of changing tastes and increasing emissions legislation that favored development of four-stroke engines.
Tony Silveira’s Kawasaki H1
One enthusiast bought a red Kawasaki H1 in 1970 and kept it up over the years, never putting a lot of miles on but keeping up the maintenance and polishing it a lot. In fact, he polished it so much that the red tank started to become dingy from repeated layers of wax.
When the original owner passed away his widow decided to sell the bike. The classic bike grapevine carried this news along, where it came to the attention of Tony Silveira, who is usually in the market for any extra-nice Japanese classics, and especially one he feels an emotional tie to. Remembering his childhood friend, Tony went to see the bike. “The widow showed it to me. I could tell that her husband had loved this bike. There have always been people who were respectful of these motorcycles. There was not a nick on it. Even the vinyl on the seat was pristine. It had the original grips and pegs, the original K series Dunlop tires, and only 1,136 original miles. The bones were good.”
Tony bought the H1, took much of it apart, and started a careful cleaning process. “I took the emblems off and detailed out years of wax. I disassembled all three carburetors and cleaned them, and I soaked the tank inside and out.” The result is the bike you see here, as original as any 1970 H1 you’ll ever come across.
Although reassembled, the bike doesn’t get around much; Tony thinks it’s too much of a time capsule to ride to the corner store. “This Kawasaki H1 is unique — it has never kissed the pavement,” meaning it’s never been down, he says. Tony has a slightly worn and less original 1969 that he rides — carefully — on a regular basis.
Why two H1s? Because he gets a thrill from actually riding an H1. “It’s an exciting bike,” Tony says. “The power kicks in and you can feel the engine. Riding one is fun. It will put a smile on your face.”
Tony says that when you ride an H1, you need to look straight ahead and not check the speedometer or the scenery. “The front end comes up too easily. Going around a corner takes finesse. You have to use caution — you can’t get on the gas in turns.” The Kawasaki vibrates some, but, Tony says, “You don’t notice the vibration — you’re hanging on for dear life!”
Yet for all its fearsome performance, the Kawasaki starts easily. “There’s a thumb stroke lever on the throttle side of the bars, it acts like a choke, then you turn on the electronic ignition. You kick two or three times and it’s off. Once it warms up, it’s eager to go,” Tony says.
Surprisingly for its time, it’s also a fairly low-maintenance proposition. “The best maintenance is to ride it. I have to synch the carbs once a year at most. The CDI ignition does away with points and condensers. The drum brakes have easy to operate star adjusters, and you replace the shoes when you run out of adjustment.”
And as long as you can resist the urge to nail the throttle, it’s actually surprisingly docile. “It is fine around town and runs well on the freeway. The double-leading-shoe front brake works well. The large, cushy seat is comfortable. The bike is not good in tight twisties, but on the straights it’s a blast.” And that, of course, is a big part of the draw for Tony, who adds, “You can hear it coming with its special sound. It’s a thrill.” MC
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Read more about the motorcycles mentioned in this article:
• 1967 Suzuki Hustler X-6
• Honda CB450: The Black Bomber
• Suzuki Titan T500
• Custom-Built Five-Cylinder Kawasaki Motorcycles