Resurrecting a Legend: Kawasaki H1 Mach III Custom

Basket Case to Asphalt Warrior: 1971 Kawasaki H1B… 

In the annals of motorcycledom, few street-going machines have earned a more notorious reputation than the original Kawasaki H1 Mach III, a 500cc two-stroke triple developed for the speed-crazed horsepower junkies of the American market. Kawasaki had only produced their first motorcycle in 1962, and they wanted to make a name for themselves in the industry — building the fastest 500 possible was just the ticket.

To that end, they enlisted the help of champion drag racer Tony Nicosia to develop an air-cooled 500cc machine with at least 60 horsepower and quarter-mile times of 13 seconds or faster. It was code-named the “N100 Plan.”

When the bike broke cover in 1969, many in the motoring media denied the bike’s performance claims. To put the naysayers to rest, Tony Nicosia uncrated a brand-new H1 at the Lions Drag Strip in Wilmington, California, and clocked a time of 12.70 seconds at 107 mph with just 7 miles on the odometer.

“The critics were not silenced but instead converted to believers who pinned Kawasaki’s success in every motorcycle magazine in the world. Over the next several years Tony would amass world and national records all across the country on the H1.” —Drag Bike

A legend was born, and the bike’s combination of blistering speed, impotent brakes, and flimsy chassis made it the original “Widowmaker,” so-named even before the introduction of the 750cc H2.

“The fact that the H1 frequently wheelied (the bike has a 57% rearward weight bias), was unstable at speed, and sounded like an incoming bombing raid cemented the bike’s legend.” –Revzilla

In the heart of Georgia’s capital, the crew at Atlanta Motorcycle Works recently completed the very special ’71 Kawasaki H1B custom you see here.

“This was a passion project we completed for a client. This was his late father’s project that he had us bring back to life. We were so excited and satisfied with the result and could not have been happier to bring his father’s motorcycle back to its former glory.”

Guided by shop foreman Mike Pacella, the project would be no light refurbishment and customization, as the bike arrived in a state of disarray, scattered across more than 10 boxes of parts — a testament to its previous life and the ambitious vision of its owner. Atlanta Motorcycle Works was honored to complete the build, turning the basket case into an resto-modded “Asphalt Warrior.”

At the heart of the resurrection is a finely tuned street porting package. The bike is running billet heads with custom porting, .5 overbore on the cylinders, new Wossner Pistons, and a crankshaft rebuilt and balanced for premix.

The bike breathes through three Mikuni VM34 carbs with ported intakes and a Higgspeed Exhaust that only heightens the power and aggression of this vintage two-stroke triple.

When it came to the rest of the build, the decision was made to elevate the braking and handling performance to more contemporary standards, better harnessing the formidable power of the mighty triple.

A stabilized 1996 GSXR front end and custom reinforced swingarm were adapted to the bike, paired with custom-tailored brake hardware for enhanced stopping power and cornering confidence.

“The result is a seamless blend of stability and agility — an invitation to carve through curves with precision and poise.”

The bike’s electronics were also upgraded to 21st century standards with an NWT Cycletronic X21 module — a small, discrete package which allows a streamlined custom wiring harness to be built specifically for each bike.

Up front there’s a digital Koso gauge to keep the rider abreast of the machine’s performance, readable even when the rest of the world is a blur of speed.

In terms of aesthetics, the bike is has been sprayed a custom pearl blue paint with meticulously applied factory decals, and the bike rolls on a set of polished 17” aluminum Excel spoke wheels, offering modern rubber and an extra pop of shine.

This 1971 Kawasaki H1B is more than another restoration — it demonstrates a deep-seated passion and reverence for vintage motorcycles and timeless design.

“This is not merely a restoration but a resurrection — an invitation to rediscover the thrill of riding with a legendary machine reborn.”

Thanks to Atlanta Motorcycle Works for bringing this legendary machine back to life and sharing the story as well. What an incredible example of a tastefully modified vintage bike, and a tribute to the original owner’s vision.

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