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Kawasaki H2 750 – The Widow Maker

Nobody can blow the original Kawasaki H2 750 trumpet like Kawasaki themselves who wrote in their catalog:

“We’ve just pulled a fast one on the competition. Named the Kawasaki 750cc Mach IV. Of all the world’s production models, it’s the fastest thing on two wheels. Faster than any Suzuki. Faster than any Triumph. Faster than any BSA, and Honda, anything.” Bennetts

Let’s get into what the Mach IV/ H2 750 was all about.

Kawasaki H2 750 Review

Kawasaki H2 750 Triple
The Kawasaki H2 750 Triple

Let’s take it back to 1971, a time when every motorcycle manufacturer had or were working towards a 750 Superbike in their line-up. 

There are many debates about which bike was actually the ‘World’s First Superbike’ but it usually ends up with all others conceding to the Honda CB750 in 1969. 

So, you have the Honda CB750, the Triumph Trident, Norton Commando and the MV Agusta 750S among others. The Japanese giants weren’t going to be left behind so they entered the game with the Kawasaki H2 750 Mach IV. 

Kawasaki had only one intention with the H2 Mach IV and that was to make it fast. Speed was the only thing that mattered and everything else came second, which included handling and fuel consumption.

The 500cc H1 Mach III had set the performance benchmark for road-going bikes but the all new Formula 750 race series had all manufacturers chasing to build the best 750cc machine they could. 

Kawasaki needed to step up to the mark and that they did for the 1972 model year with the all new Kawasaki H2 Mach IV 750. 

However, Kawasaki opted for simplicity over and above innovation and aiming for technical advancement with the engine. Instead of turning to reed-valves that other manufacturers were implementing in their two strokes, Kawasaki decided to stick to a piston-port design. 

The 3 cylinder engine was matched with three Mikuni carbs and Kawasaki’s new CDI was fitted. You would be doing well to get 22 miles a gallon out of the air cooled triple-cylinder two stroke engine.

It was a basic set-up but it was fit for the job and exceeded what was already on the market. The original Triumph Trident triple was the closest comparison and that made 58 horsepower, the new H2 750 pumped out 74 horsepower. 

Kawasaki had built a virtually bullet-proof engine, with over-engineered crank components to look after the bottom end and beefy crankcases holding everything together nice and solid. 

The size of the engine is also something to marvel at as it is completely in proportion to the bike itself and is very modern looking even all these years later.

On the Road

If you manage to keep the revs down below 5000 rpm the bike can potter around all day long, it will inevitably cough and make it known how disgusted it is, but it will do it. However, rising just to 6,000 rpm the bike feels completely different.

Peak torque and power meet within 300 rpm of each other and when they collide the hit is huge and terrifying. There was no other production motorcycle at the time that could match the Kawasaki H2 750 performance. 

The Mach IV was notoriously anti-social in terms of both the noise they made and the pollution sent out of the exhaust. To be deemed anti-social in the 1970’s was saying something, by today’s standards you would likely feel the entire wrath of Greenpeace after a blip down the road. 

The triple cylinder engine would scream to 120 mph, pumping out oily blue smoke as it went. Engine vibration was immense and would have you holding on for dear life. It was arm-wrenchingly fast and therefore not for everyone. 

Matched with a frame that wasn’t the strongest and a basic suspension package, wheelies were all too common as were high-speed tankslaps. Pair all of that with pretty shoddy brakes which were typical of the era and what you have is a disaster waiting to happen. 

The lightweight tubular cradle frame was incapable of handling the motor, it would flex and weave making corners and uneven roads impossible to navigate safely. Two steering dampers were fitted but they made little difference. 

The weight sat over the rear wheel, the wheelbase was short and the short swingarm meant that the front wheel would lift anytime there was a little too much power used. 

In 1974 the revised Kawasaki H2 750 came replacing the Mach IV but they remained essentially the same machine. It was a marginally less crazy motorcycle with a longer wheelbase, more relaxed forks, and 3 ponies were missing but essentially it was still an absolute monster. 

By the mid-70’s stricter safety, environmental and noise regulations were coming into play and this was the beginning of the end for all two-strokes, especially big ones, so the last Kawasaki H2 disappeared in 1975 in a puff of blue smoke. 

It was replaced with the Z750 and that was the end of that, although in its production run the H2 had earned itself the title ‘The Widowmaker’. 

Why the Widowmaker? It would take a skilled rider to truly master the Kawasaki H2 750 and if they could then it was the fastest production bike available. However, for the average joe, the H2 was an untamed stallion that many wouldn’t master.

Not to say that reputation needs to follow the bike today, as if you want a H2 for modern riding, some simple modifications like upgrading the brakes and suspension could lead you to have a hell of a lot of two-stroke fun. As you blast past your mates, you will be known as one of the few to tame the ‘Widow-Maker’! 

On the Track

Alongside the Kawasaki H2 750 development in 1971, Kawasaki had begun work on a H2R to compete in the new 750cc racing class and the factory triples had some success.

In 1972 Yvon Duhamel won races at Road Atlanta and Talladega Speedway, Paul Smart also won at the Ontario Motor Speedway.

By 1973 FIM regulations meant that road bike cylinders had to be used in the races so Kawasaki had to swap out the cylinders they had cast specifically for their race bikes. The triples produced for that season had a number of failures and were not as effective. 

The H2R won five out of nine AMA road races for the 1973 season. 

In 1974 Kawasaki came up against the Yamaha TZ750 and the H2R was no match in a racing context. 

The KR750 would be Kawasaki’s next racing motorcycle which used the basic foundation of the Kawasaki H2 750. The ‘Green Meanie’ team would go on to have a series of victories on the KR750 including Mick Grant winning the Isle of Man TT in 1977. 

Kawasaki H2 750 Specifications

Engine and Transmission

  • Two-Stroke, Transverse, Three-Cylinder
  • 748cc
  • Bore x Stroke – 71 x 63mm
  • Air-Cooled
  • Compression Ratio – 7.1:1
  • Oil Injection
  • Induction – 3 x 30mm Mikuni Carburetors
  • Ignition – CDI
  • Kick-Start
  • Max Power – 74 horsepower at 6,800rpm
  • Max Torque – 77.4Nm at 6,500rpm
  • Clutch – Wet, Multi-Plate
  • Transmission – 5 Speed gear box
  • Final Drive – Chain

Chassis and Dimensions

  • Frame – Tubular, Double Cradle
  • Front Suspension – Telescopic Forks
  • Rear Suspension – Dual Shocks, Preload Adjustable
  • Front Brakes – Single 295mm Disc
  • Rear Brakes – 203mm Drum
  • Wheelbase – 1410mm
  • Seat Height – 795mm
  • Ground Clearance – 183mm
  • Dry Weight – 192kg
  • Fuel Capacity – 16.7 Litres

Kawasaki H2 750 Top speed

126 mph is the claimed top speed for the H2 750. It is said to do 0-60 mph in 5 seconds flat and the standing quarter mile in 12.3 seconds reaching speeds of 105 mph. 

How much is a Kawasaki H2 750 Worth?

Kawasaki H2 750 – The Widow Maker Kawasaki H2 750 – The Widow Maker

Check out the current H2 750 listings on eBay

I may earn a commission if you make a purchase, at no additional cost to you.

In the UK prices vary quite significantly for a Kawasaki H2 750 from £12,000-£20,000, this is all condition dependent.

At any given time you will find a good choice of 750 H2 bikes on eBay UK.

In the USA prices sit somewhere between $7,500-$15,000. They seem to be cheaper yet rarer in America and you may have to cast your net further than eBay USA who seem to have at best 2 or 3 listings at any given time.

Smart Cycle Guide is another place to check in the US with several listings. 

On 2040 Motos, this 1974 H2 is up for $12,900 and has been lovingly restored to a very high standard. 


In 2021 I am not sure who wouldn’t want to get their hands on a classic 1970s two-stroke, three-cylinder piece of history and one of the fore-runners of superbikes? 

Sure, the Kawasaki H2 750 is the definition of a hooligan bike and makes for some sketchy riding at speed. It was aggressive, outrageous and short-lived like all of the worlds best icons. 

So, sign me up, let’s add one to the mental collection and maybe one day to the physical collection. 

My Grandad had a Kawasaki H2 750 sat in his garage for as long as I can remember. I was only 15 when he passed, which is my excuse for being too young to protest at the bike being sold. Had I known then, what I know now, I would have more than just pictures to reflect back on.

Please support by sharing

Paul Lucas

Wednesday 24th of August 2022

Just bought a 1973 H2 750 today 160 miles from new absolutely mint condition I couldn’t be happier

Mike Martin

Wednesday 6th of July 2022

I bought a new one in 1972 . It was a blast and I had several close calls on it. I sold it and bought a KZ900. I servived them both.


Tuesday 10th of May 2022

I was a street racer back in the day. How I didn't crash and or kill myself on my blue baby is a mystery and in God's hands. My sweetheart 💞 told me she'd marry me if I sold the bike. The new owner totalled it on Day Two and nearly killed himself. The Widowmaker was rendered obsolete when Kawasaki came out with the 900!

Martin Hambleton

Tuesday 28th of June 2022

I have just bought a 72 H2 750, UK registered bike. They have legendary status to this day. No matter what any other manufacturer builds now, the likes of the H2 750 will never be seen again. 20 miles per gallon, or less, smokey, noisy and doesn't handle very well at all. The front wheel will go skyward if you get over ambitious with the right hand. The brakes are inadequate. What's not to Love? Whenever I go out on it people will gather round it with fascination. Yes I am in love with it. She is as antisocial as they come with all the vices 🏴‍☠️❤️