800cc Widowmaker: Kawasaki “KH750” Triple

Kawasaki KH750

An 800cc, 120+ hp Triple from Ralf Kraemer…

In the late 1960s, Kawasaki wanted to create a 500cc two-stroke motorcycle that could boast 60 horsepower and a 1/4-mile time below the 13-second mark. The result would be one of the most notorious motorcycles of all time, the Kawasaki H1 triple. It was one of the most uncompromising sporting machines ever devised, disregarding noise, pollution, and handling concerns in favor of blazing down the drag strip in the fastest time possible.

“The fastest and best accelerating road machine ever produced, being capable of 124 mph and 12.4 sec. for the standing start quarter mile.” –Kawasaki factory claim

Kawasaki KH750

A mystique would quickly develop around the Kawasaki triple, known as the “Widowmaker” for its flexible chassis, questionable brakes, and eagerness to wheelie — blow on the throttle and the front wheel would lift. By the mid-1970s, however, the oil crisis and new anti-pollution standards — the same forces that sounded the death knell of the American muscle car — were knocking on the Widowmaker’s door. In 1976, the world would get its final H1 triple, renamed the KH500 to conform with the company’s model-naming conventions.

“It was still the same wicked-hearted machine, just with styling changed slightly to reflect Kawasaki’s Z1, a model that was currently the company’s biggest seller.” —Mecum

Kawasaki KH750

The bike was actually down on power slightly, making just 52 bhp, but it was still a formidable machine. What’s more, there was no 750cc H2 model that year — only the KH250, KH400, and KH500.

Enter our friend Ralf Kraemer of Triples Klinik GL who had one of these bikes when he was 22. In fact, this is the actual bike that Ralf owned! More than 30 years after he first purchased the bike, Ralf wondered what, in an alternative universe, the 750cc version would have been like:

“If Kawasaki had built a 750 Kawasaki in 1977, what would a KH750 have looked like?”

Kawasaki KH500
The original KH500.

The bike is now running an 800cc H2 engine with Jim Lomas pipes and 34mm Mikuni carbs that makes a reported 120 horsepower.  What’s more, the bike has been lowered four centimeters front and rear, outfitted with modern rubber, and it’s sporting Dunstall rear sets for a more aggressive riding position.

One of the best parts of this 55-year-old Triple is that it’s a sleeper — a vintage machine capable of surprising the latest two-wheeled weaponry. Says Ralf:

“It’s fun to leave some modern bikes at the traffic lights.”

Below, we get the full story on this 800cc Widowmaker!

Kawasaki “KH750” Triple: Builder Interview

Kawasaki KH750

• Please tell us a bit about yourself, your history with motorcycles, and your workshop.

This was my first triple Kawasaki KH500. I was 22 years old. Now 59 years young.

Kawasaki KH750

• What’s the make, model, and year of the bike?

Kawasaki KH500 from 1976.

Kawasaki KH750

• Why was this bike built?

If Kawasaki had built a 750 Kawasaki in 1977, what would a KH750 have looked like? There were only the Kawasaki KH250, KH400 and KH500.

Kawasaki KH750

• What was the design concept and what influenced the build?

It should look like the Kawasaki KH series in terms of design. Based on a dragster.

Kawasaki KH750

• What custom work was done to the bike?

The motorcycle is my motorcycle and not for sale. 800cc and more than 120HP. Spacer for the cylinder, special pipes from Jim Lomas. Carbs 34mm from Mikuni. Lowered 40mm at the front and back. RAMAIR airfilter, Dunstall relocated footpegs, 40mm handlebar riser and NGK spark plug connector. Front tyre 100/80-18 and rear 140/70-18 Bridgestone.

• Does the bike have a nickname?


Kawasaki KH750

• Can you tell us what it’s like to ride this bike?

Despite the lowering, you can still get around the corners very well. It’s fun to leave some modern bikes at the traffic lights.

Kawasaki KH750

• Was there anything done during this build that you are particularly proud of?

It’s nice that my first motorcycle is back on the road with a lot of power.

Follow the Builder


  1. Gabe Ets-Hokin

    This article leaves out the most crucial bit of info–the motor! How did he get it to 750cc? New cylinders? Stroked? Bored? Both?

  2. Alan Everett

    Of course there was an original KH750, how do you think Kawasaki got homologation for the original F750 races?

    • All right, bud — please show us an original 1976 Kawasaki KH750 for evidence.

      Obviously there was the earlier Kawasaki H2 750 — where the engine in this build comes from — but that was not produced as a ’76 KH750 model with the new styling of the other KH models.

      • Of course, you are absolutely correct, its just that the article is worded in a way that would make the reader believe the largest triple they produced was 500.

  3. Hello. I’m currently restoring a 1974 H2 750. I need help finding replacement parts. Can anyone direct me to good sources please.

  4. I’m about to buy a couple of basket case H2’s. A 71 and a 74. I sold my 750 in 1980, it was a 72….mint. Being a fair to good rider, it challenged me to try and kill myself. My brother had dumped it at 90 mph and put himself in the hospital, but wearing all the scars today from that “wheelie gone bad”. I rebuilt the bike with expert hands and a few rides on it told me I’d better sell it to a more responsible rider. The guy crashed at nearly 100 mph not 2 months after buying it. Just about died, but survived with lifelong crippling injuries. This bike dares you, they should have never been built. But you know what? They don’t have a mind, but they will get you to loose your cool. When torque and max horsepower intersect, the feeling is indescribable, dangerous, and your mind goes blank. Anyone who can manage this bike should never let go of it. This bike defines insanity, keep it from the hands of someone who might get maimed or killed. I love ’em. You will never know why….until you ride one.

  5. Brian Fawcett

    I had a 350 S2 which was a bit of a “Wild Card” back in the day. I bought it second hand, it was in a bit of a sorry state and found out that it was very rare (at least in Europe) due to Insurance Companies refusing to insure them from new as there were too many accidents. Basically the S2 was a beast………..not just an overbored 250. It still had the very flexible frame, lousy suspension and tyres that felt they were made of soap. I beefed mine up a bit by replacing the rubber bushings with machined bronze and providing grease nipple points. Then I put Girling shocks on the back and put engine oil in the front forks after a rebuild then drilled out the Fork caps and put Shraeder valves to allow air pressure inside. Then I changed the tyres to Michelin PZ2 which are actually racing tyres that were still road legal. I could take this baby down to the pegs at any speed and the tyres would still hang on provided the road was dry……………talking of dry, I had to change the coils for Suzuki due to the OEM coils and leads arcing out as soon as a dark cloud appeared in the sky. Back to the front end……….I had to have the front drum skimmed and the brake shoes relined by a professional to solve the Factory issues. Man this guy really know what he was doing. I swear this front brake was abetter than any Disc brake on the market, all it needed was skilled finesse to make it work properly. The death wobble!………..I almost had one but pulled a wheelie to stop it happening. Very scary! so then I installed a horizontal hydraulic damper from some aftermarket racing supplier. This stopped the problem. After another 6 months I tried to buy an electronic ignition unit but in those days they were only for racing so no option to charge the battery and no lighting so I sold it and bought a Z1300…….happy days!

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