Kawasaki H2 Mach IV Speed Legend Amid Controversy

If there ever was a motorcycle that perfectly embodied the phrase "dangerously beautiful," it would be the Kawasaki H2 Mach IV, born in the early 1970s. This machine, designed with one singular purpose—ultimate speed—earned both the terrifying nickname "The Widowmaker" and a permanent place in motorcycle lore as an icon of its wild era.

The early 1970s witnessed an unprecedented battle for supremacy among motorcycle manufacturers. Norton's 120mph Commando, MV Agusta's 750S, and Ducati's 750SS all vied for dominance in the newly established Formula 750 racing series. Kawasaki's response—the Mach IV—would become legendary for its raw power and distinctive character.

Kawasaki's approach with the H2 Mach IV was brutally simple: prioritize speed above all else. Noise levels, emissions, fuel efficiency, and even handling were secondary considerations. The company's 1972 marketing materials boldly declared: "We've just won the competition. This motorcycle is called the Kawasaki 750cc Mach IV. Among all production models in the world, it's the fastest two-wheeled machine. Faster than any Suzuki. Faster than any Triumph. Faster than any BSA, Honda, or any other model."

At its heart lay a 748cc air-cooled, two-stroke inline triple with piston port induction. Three 32mm Mikuni carburetors fed the beast, while Kawasaki's proprietary Capacitor Discharge Ignition (CDI) system handled spark duties. This deceptively simple package produced a staggering 74 horsepower—16 more than its closest competitor, the Triumph Trident.

With a dry weight of just 184kg (only 8kg heavier than Kawasaki's previous 500cc H1 Mach III), the Mach IV delivered acceleration and a top speed of 126mph that left contemporary riders and journalists breathless.

The H2's Achilles' heel was its frame. The lightweight tubular cradle design couldn't properly contain the engine's massive power output. In corners, the frame would flex alarmingly, while rough roads induced terrifying wobbles. Kawasaki's solution—dual steering dampers (one friction, one hydraulic)—proved inadequate.

The bike's weight distribution, heavily biased toward the rear wheel and combined with a short swingarm, made wheelies frequent and difficult to control. The 74 horsepower arrived in a narrow powerband, requiring expert throttle management.

In skilled hands, the Mach IV was the fastest production motorcycle on earth. For less experienced riders, it became a potential death trap—earning its grim nickname.

By 1974, Kawasaki attempted to tame the beast with chassis modifications and engine tuning. However, even these changes couldn't mask the H2's fundamentally wild nature. Its ultimate downfall came not from safety concerns alone, but from the 1970s oil crisis and tightening emissions regulations. The last H2 disappeared in 1975, marking the end of an era for large-displacement two-stroke motorcycles.

Despite its brief production run, the H2 Mach IV left an indelible mark on motorcycling. It represented both the pinnacle and the pitfalls of 1970s performance engineering. Today, well-preserved examples command premium prices at auction, cherished by collectors for their rarity and historical significance.

• Engine: Air-cooled two-stroke inline triple
• Displacement: 748cc
• Bore x Stroke: 71 x 63mm
• Compression Ratio: 7.0:1
• Max Power: 74 hp @ 6,800 rpm
• Max Torque: 7.9 kg-m @ 6,500 rpm
• Carburetion: 3 x Mikuni VM32SS
• Transmission: 5-speed
• Front Brake: Single disc
• Rear Brake: Drum
• Dry Weight: 184 kg
• Top Speed: 126 mph (203 km/h)

While today's supercharged Kawasaki H2 shares its predecessor's name, the two machines are fundamentally different. The modern H2 serves as both a technological showcase and a tribute to its infamous ancestor—proof that while motorcycle engineering has matured, the pursuit of extreme performance remains alive.