Kawasaki H2 Mach IV
Encyclopedia
The Kawasaki H2 Mach IV was a 750 cc 3-cylinder two-stroke production motorcycle manufactured by the Kawasaki. The H2 was a Kawasaki triple
sold from 1972 through 1975.
A stock H2 was rated at 12.0 secs for the quarter mile, and about 12 seconds for 400 m from a standing start. The H2 became the undisputed king of the streets, even beating legendary muscle cars of the era such as the Dodge Hemi Cuda. It was notoriously dangerous, being prone to up-and-over wheelies and speed wobbles. The dangerous handling characteristics arising from its mediocre frame design caused it to be nicknamed the "Widowmaker" by motorcycle enthusiasts of the 1970s.
introduced in 1969. The H2 engine was a 3-cylinder two-stroke with an engine displacement
of 748 cc (45.65 cubic inches) which produced 74 hp @ 6800 rpm, a power-to-weight ratio of 1 hp to every 6 pounds of weight. This was an entirely new engine and not a bored-out 500. The powerband was only 2800 rpm wide, the H2 was gutless below 3500 rpm and redlined at only 7500 rpm. Ridden hard, gas mileage was around 18-22 mpg.
The 1972 H2 had a front disc brake
, a capacitor discharge ignition
system, chain oiler, and steering friction damper.
In 1973, there were no mechanical changes.
In 1974 the H2 engine was modified for more civilized performance at the expense of raw power. The race tail was slimmed down from the previous year. A steering oil damper and check valve were added. The power was reduced to 71 hp @ 6800 rpm. A longer swingarm improved stability. The final model had a weight of 208 kilograms (458.6 lb)
The 1975 model year showed a repositioning of the steering damper.
Kawasaki Triples were air-cooled, and the crankshafts were pressed together. This made it possible to cut an engine apart, press up extra sections of the crankshaft, re-weld different sections of the cases, and make multi-cylindered motorcycles. The ignition system and carburetors had to be redone. Four-cylinder 1000 cc H2s were known to exist.
on the H2 as well as on the 350 cc S2 Mach II
. The race tail covered most of the taillight assembly behind the seat and allowed for a less conspicuous rear fender. This design innovation would be copied and seen on the 1977 Yamaha RD400 and nine 1978 Suzuki
models beginning with the GS1000 down to 250 cc bikes.
Kawasaki triple
The Kawasaki Triples were a range of 250 cc to 750 cc motorcycles Kawasaki exported from 1969 to 1980. The engines were air-cooled, three cylinder, two-stroke with two exhaust pipes exiting on the right side of the bike, and one on the left....
sold from 1972 through 1975.
A stock H2 was rated at 12.0 secs for the quarter mile, and about 12 seconds for 400 m from a standing start. The H2 became the undisputed king of the streets, even beating legendary muscle cars of the era such as the Dodge Hemi Cuda. It was notoriously dangerous, being prone to up-and-over wheelies and speed wobbles. The dangerous handling characteristics arising from its mediocre frame design caused it to be nicknamed the "Widowmaker" by motorcycle enthusiasts of the 1970s.
History
The H2 was a direct result of the success of the 500 cc Kawasaki H1 Mach IIIKawasaki H1 Mach III
The Kawasaki H1 Mach III was a high-performance two-stroke 500cc production motorcycle manufactured by Kawasaki Motorcycle Corporation. It was sold in the U.S. and abroad from 1969 through 1975.-History:...
introduced in 1969. The H2 engine was a 3-cylinder two-stroke with an engine displacement
Engine displacement
Engine displacement is the volume swept by all the pistons inside the cylinders of an internal combustion engine in a single movement from top dead centre to bottom dead centre . It is commonly specified in cubic centimeters , litres , or cubic inches...
of 748 cc (45.65 cubic inches) which produced 74 hp @ 6800 rpm, a power-to-weight ratio of 1 hp to every 6 pounds of weight. This was an entirely new engine and not a bored-out 500. The powerband was only 2800 rpm wide, the H2 was gutless below 3500 rpm and redlined at only 7500 rpm. Ridden hard, gas mileage was around 18-22 mpg.
The 1972 H2 had a front disc brake
Disc brake
The disc brake or disk brake is a device for slowing or stopping the rotation of a wheel while it is in motion.A brake disc is usually made of cast iron, but may in some cases be made of composites such as reinforced carbon–carbon or ceramic matrix composites. This is connected to the wheel and/or...
, a capacitor discharge ignition
Capacitor discharge ignition
Capacitor discharge ignition or thyristor ignition is a type of automotive electronic ignition system which is widely used in outboard motors, motorcycles, lawn mowers, chainsaws, small engines, turbine-powered aircraft, and some cars...
system, chain oiler, and steering friction damper.
In 1973, there were no mechanical changes.
In 1974 the H2 engine was modified for more civilized performance at the expense of raw power. The race tail was slimmed down from the previous year. A steering oil damper and check valve were added. The power was reduced to 71 hp @ 6800 rpm. A longer swingarm improved stability. The final model had a weight of 208 kilograms (458.6 lb)
The 1975 model year showed a repositioning of the steering damper.
Modifications
The ability to cheaply modify the engines for higher performance by porting the cylinders, milling the cylinder heads, and installing expansion chamber exhausts maintained their popularity for some time in drag racing. An H2 still holds the record for the fastest nitrous injected 750 cc motorcycle, with a standing quarter-mile of 7.776 secs at 170 mph, and the record for a normally aspirated 750 cc motorcycle with a standing quarter-mile of 8.24 secs at 153 mph.Kawasaki Triples were air-cooled, and the crankshafts were pressed together. This made it possible to cut an engine apart, press up extra sections of the crankshaft, re-weld different sections of the cases, and make multi-cylindered motorcycles. The ignition system and carburetors had to be redone. Four-cylinder 1000 cc H2s were known to exist.
The racing tail
In 1972, Kawasaki designers took a progressive leap forward in overall design appearance with the creation of the first race tailRace tail
The race tail or motorcycle tail is a functional feature of a Grand Prix motorcycle located behind the motorcycle seat. It is designed to maintain a smooth flow of air from the rider over the motorcycle's rear.-Origin:...
on the H2 as well as on the 350 cc S2 Mach II
Kawasaki S2 Mach II
The Kawasaki Mach II was a Kawasaki standard motorcycle, made from 1972 through 1973.-History:The Mach II was a direct result of the widespread success of the Kawasaki H1 Mach III 500 cc introduced in 1969. The Mach II's engine was a 3-cylinder two-stroke with an engine displacement of...
. The race tail covered most of the taillight assembly behind the seat and allowed for a less conspicuous rear fender. This design innovation would be copied and seen on the 1977 Yamaha RD400 and nine 1978 Suzuki
Suzuki
is a Japanese multinational corporation headquartered in Hamamatsu, Japan that specializes in manufacturing compact automobiles and 4x4 vehicles, a full range of motorcycles, all-terrain vehicles , outboard marine engines, wheelchairs and a variety of other small internal combustion engines...
models beginning with the GS1000 down to 250 cc bikes.
Specifications
- Engine: Air-cooled, two-stroke, transverse three-cylinder,
- Engine capacity: 748 cc (45.65 cubic inches)
- Bore x Stroke: 71 x 63 mm
- Compression Ratio: 7.3:1
- Induction: 3x 32 mm Mikuni carbs
- Starting and ignition: Kick start battery and coil
- Max Power: 74 hp @ 6800 rpm
- Max Torque: 7.9 kg-m @ 6500 rpm
- Transmission: 5-speed, chain drive.
- Frame: Double tubular steel cradle
- Front: Suspension: Telescopic hydraulic forks
- Rear Suspension: Dual shocks, Swing arm
- Brakes: Single disc (front) Drum brakeDrum brakeA drum brake is a brake in which the friction is caused by a set of shoes or pads that press against a rotating drum-shaped part called a brake drum....
(rear) - Dry-Weight 205 kg (423 pounds)
- Fuel Capacity: 17 liters (4.49 gallons)