Kawasaki H1 500 Mach III


Make Model

Kawasaki H1 500 Mach III




Two stroke, transverse three cylinder, piston valve


498 cc / 30.4 cu-in
Bore x Stroke 60 х 58.8 mm
Cooling System Air cooled
Compression Ratio 6.8:1
Lubrication Injectolube, automatic pressurized injection


3x Mikuni VM28SC carburetors


Starting Kick

Max Power

60 hp / 45 kW @ 7500 rpm

Max Torque

56 Nm / 42.3 lb-ft @ 7000 rpm
Clutch Wet multi-disc


5 Speed 
Final Drive Chain
Frame Double tubular steel cradle

Front Suspension

Telescopic hydraulic forks

Rear Suspension

Dual shocks, swing arm

Front Brakes

200mm Drum

Rear Brakes

180mm Drum

Front Tyre


Rear Tyre

Wheelbase 1400 mm / 55 in

Dry Weight

174 kg / 384 lbs
Wet Weight 188 kg / 414 lbs

Fuel Capacity 

15 Litres / 4.0 US gal
Standing ¼ Mile   12.4 sec

Top Speed

200 km/h / 124 mph


The market for motorcycles in 1968 had been changing from time, utilitarian transport to more aggressive sporting motorcycles that disregarded fuel economy and noise, in favor of quicker quarter mile times, which were prominently advertised by manufacturers. While Kawasaki had an inline-four four-stroke in development, it was not going be ready in time to upstage the 1969 Honda CB750, so instead they moved up the release of their conventional piston port two-stroke triple to "make a real splash". They turned to the N100 Plan, a project begun in June, 1967, whose intent was to design the most powerful production motorcycle engine in the world. They first considered increasing the bore of an existing engine but instead created an all-new engine, experimenting with both inline and L cylinder arrangements, with both two and three cylinders.

They settled on an inline-three arrangement after testing showed that an inline layout did not adversely affect cooling of the middle cylinder.
The result of this project was the H1 Mach III, with a 15° inclined, inline-triple 498 cc (30.4 cu in) engine, first produced in September, 1968, 14 months after the N100 project began. The new model did indeed sell well with young men in the late 1960s, with total production eventually exceeding 110,000 units, though it was unpopular with authorities. The bike gave Kawasaki a "rebel" image, "outside the law", which played well with sport bike riders. The racing version, the H1R ridden by Ginger Molloy, took second place in the 1970 Grand Prix World Championship.

The H1 was the first multi-cylinder street motorcycle to use capacitor discharge ignition (CDI) which operated through an automotive style distributor, previously only used in off-road single cylinder motorcycles. The first version of this electronic ignition was overly complex and proved unreliable, so Kawasaki gave up on it briefly, using traditional breaker points, one set for each cylinder, in 1972. For the 1973 H1D, a redesigned CDI was used, which was more reliable with a hotter spark at lower engine speeds, which in turn made it possible to re-jet the three Mikuni carburetors for a wider power band. The US version came with a high handlebar, but a low bar was used in the European market. The H1 was loud, due to the use of racing expansion pipes, brought barely within the limits of noise regulations for the period.

The bike had both detractors and enthusiastic fans, who either complained of poor handling and tendency to wheelie, or praised the power, light weight, and tendency to wheelie. Wheelies could occur unintentionally even during cornering. The two-stroke engine's suddenly increasing power curve, with little response until a rush of power about 5,000 rpm, contributed to this unexpected liftoff of the front wheel, creating "fearsome reputation" from tales of "scary performance." The Mach III became known to its critics as "dangerous for inexperienced riders".

The H1 had a high power-to-weight ratio for the time, 45 kW (60 hp) and a dry weight of 384 pounds (174 kg), comparable to a top racing motorcycle, but had generally poor handling and weak drum brakes front and rear. It could accelerate from 0 to 1⁄4 mi (0 to 0 km) in 12.4 seconds. However, Motorcycle Classics said in 2009 that the frequent complaints about the brakes of the H1 by modern writers did not account for the generally poor braking of all motorcycles of the period, noting that in a 1970 Cycle magazine comparison of seven top sport bikes of the time, the H1's braking performance was second only to the Honda CB750.

The notoriously flexible frame was strengthened over the years, along with shifting the center of gravity to decrease the tendency to wheelie. While Kawasaki was working to "make the H1 acceptable in civilized society", they also released the delayed inline-four four-stroke, the Z1, in 1972, which had adequate brakes and handling, comfortable seating, and did not guzzle fuel. The sales success of the Z1 demonstrated that there were more buyers for higher-priced but less obnoxious sport bikes, than buyers who would accept numerous compromises for an extremely fast motorcycle at a low price. More stringent noise and pollution regulations also contributed to the end of the H1 500 production, whose final year was 1976.

The Mach III H1 500 subsequently has been of great interest to collectors and historians of motorcycles, often appearing on lists of most significant motorcycles and, with some irony, "worst bikes" lists. Cycle World semi-seriously joked that the bike was one of the "10 Worst" for its total compromise of good qualities other than speed, and that the bike "introduced" to America the body cast and liability lawsuit. The H1 was included in the Guggenheim Museum's 1999 The Art of the Motorcycle exhibition in New York, Chicago, Las Vegas, and Bilbao, Spain.

Motorcycle historian Clement Salvadori noted in the Guggenheim's catalog that the H1, "was one of the least useful motorcycles available on the market" yet still sold very well because, in the heyday of American muscle cars where quarter mile times were paramount to the young male target buyer, it "could blow just about anything else off the road — for less than $1,000." Roland Brown agreed that it could "beat almost anything away from the lights." Salvadori added that "Motorcycle lore has it that very few original owners of the Mach III survived." While older Baby boomers collected classic brands of the 1950s and 1960s like BSA, Norton and Triumph, a younger generation of motorcycle collectors was nostalgic for H1 Mach IIIs along with other bikes of the era, Honda CBs and CLs, Yamaha RD350s and Suzuki Hustlers.

Source Wikipidia