Kawasaki Z1: review, history, specs

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Kawasaki Z1
Also called Z1, Z900, KZ900, Z1A, Z1B
Production 1973 - 1975
Class Superbike
Successor Kawasaki KZ900A
903cc air-cooled DOHC inline-four 2 valves per cylinder
Bore / Stroke 66 x 66mm
Compression ratio 8.5:1
Top Speed 130mph
Horsepower 81.94 HP (61.1 KW) @ 8500RPM
Torque 53.84 ft/lbs (73.0 Nm) @ 7000RPM
Fuel System 4x Mikuni VM 28mm carburetors
Spark Plug NGK B8ES 73-75
Battery YUASA 12N14-3A 73-75
Transmission 5-Speed Return Shift
Final Drive Chain: 630x92
Front Sprocket 15T
Rear Sprocket 35T
Frame tubular steel, double cradle
Suspension Front: 36mm Telescopic forks
Rear: Dual shock, 5-way preload adjustment
Brakes Front: Single 296mm disc 2 piston caliper
Rear: 200mm drum
Front Tire 3.25-19 73-75
Rear Tire 4.00-18 73-75
Wheelbase 1498.6 mm / 59.0 in
Seat Height 812.8 mm / 32.0 in.
Weight 230 kg / 507 lbs (dry), 247.6 lbs / 546 lbs (wet)
Oil Filter K&N KN-401
Recommended Oil K-tech 10W-40
Fuel Capacity 18 Liters / 4.7 gal
Fuel Consumption 45 mpg (average)
Related Kawasaki KZ900A
Kawasaki KZ1000A
Kawasaki Police Motorcycles
Competition Honda CB750K
Triumph Trident
Suzuki GT750
Manuals Service Manual

Reviews ·

The Kawasaki Z1 was a Air cooled, four stroke, transverse four cylinder, DOHC, 2 valves per cylinder superbike motorcycle produced by Kawasaki from 1973 to 1975. Max torque was 53.84 ft/lbs (73.0 Nm) @ 7000 RPM. Claimed horsepower was 81.94 HP (61.1 KW) @ 8500 RPM.


Kawasaki's earlier two and three-cylinder bikes such as the H1, and H2 had bestowed Kawasaki with a high performance image. But these bikes had known problems: excessive fuel consumption, noise, vibration, and less than perfect handling. Their sparse comfort relegated them to the role of street racer. Kawasaki engineers had outlined these limitations of their two-stroke triples as early as 1967. This led to the beginning stages of planning a four-stroke super cruiser in the mold of the 1000cc Vincent, that could be ridden in any situation, and would be "THE" bike all experienced riders lusted after.

New York Steak[edit]

The Kawasaki Z1 gave the world its first true superbike. Introduced in late 1972, the Z1 was Kawasaki's first four-cylinder, four-stroke motorcycle. During its planning stages it was called the codenamed the T-103 and nicknamed the 'New York Steak'. Before the introduction of the Honda CB750K to the world at the October 1968 Toko Motor Show, Kawasaki had already sent a mock-up double overhead camshaft Z1 to US Kawasaki's Sam Tanegashima. Honda's head start caused Kawasaki to be patient and carefully judge the revolutionary bike's impact.


The Z1 became the "King of the Road" and an industry leader; as the first production motorcycle to bring such high performance and prestige to the general public. Cycle Magazine recorded a standing quarter mile time of 12.83 seconds @ 101.7 mph.

Impact on the industry[edit]

All other manufacturers had to change their mindset to keep up with popularity of this motorcycle. By the end of the decade all Japanese manufacturers had developed machines to rival the Z1 which were almost direct clones of its engine configuration and integral body panels.

These bike wars directly lead to the demise of the flagging BrItish motorcycle industry.The American motorcycle industry (mainly Harley-Davidson) was also on its last legs and was only saved by radical restructuring and inventive financing.

Design changes[edit]

The basic design of the Z1 remained relatively unchanged until the early 1980s with the exception of increased engine displacement (1015cc). This model is also the basis for the motorcycle used by most police forces across the United States to this day.


Only recently (2005) did Kawasaki announce that it would discontinue production of the police model, 25 years after the production on the consumer model and 32 years after its introduction.


A 63.5mm bore x 63.5mm stroke result in a displacement of just 903.0 cubic centimeters.


The bike has a 5 Speed transmission.


It came with a 3.25-19 front tire and a 4.00-18 rear tire. Stopping was achieved via Single disc in the front and a Drum in the rear. The front suspension was a Telescopic forks while the rear was equipped with a Dual shocks.

1973 Z1[edit]

  • Color
    • Fuel Tank: Candy Yellow/Green, Candy Orange/Brown (UK & Europe); Candy Orange/Brown (US)
    • Front Fender: Chrome
  • Engine No.: Z1E000001-
  • Frame No.: Z1F-000001-
  • Parts Catalog No.: 99997-603, (E) 99997-608S
  • Owner's Manual No. : 99997-800
  • Shop Manual No. : 99997-700

The First Z1.

1974 Z1A[edit]

  • Color
    • Fuel Tank: Candy Tone Brown/Orange, Candy Tone Yellow/Green
    • Front Fender: Chrome
  • Engine No.: Z1E020001-
  • Frame No.: Z1F-020001-
  • Parts Catalog No. : 99997-627, (E) 99997-627-01S
  • Owner's Manual No. : 99997-808, (E) 99997-021, (F) 99983-009, (I) 99983-010, (W) 99983-011
  • Shop Manual No.: 99997-700

Major changes for this model were the silver engine finish, redesigned tank and tailpiece markings and a stop lamp failure light in the tachometer. The idiot light cover was also changed, the warning lights were now placed in a different order. In mid 1974 there was a slight carburetor change to improve cold running. At the end of 1974 Kawasaki had produced over 80,000 units of the Z1 and Z2. The best gets better.

1975 Z1B[edit]

  • Color
    • Fuel Tank: Candy Super Blue, Candy Super Red
    • Front Fender: Chrome
  • Engine No.: Z1E047500-
  • Frame No.: Z1F-047500-
  • Parts Catalog No.: 99997-627-50S, (E) 99997-627-51S
  • Owner's Manual No.: 99997-832
  • Shop Manual No.: 99997-700
  • Major Changes: Color and marking. Special chain provided with sealed-in grease. Automatic chain oiler discontinued.

Kawasaki dropped the automatic chain oiler in favor of an o-ring chain. The paintwork and markings were changed including larger side panel badges. The switchgear was slightly cosmetically changed and the Speedo was now in 10-mph increments. The fuel tap was changed from black to silver and the carbs were modified to improve performance. The front forks received revised dampers and softer springs. To improve low speed running there was a new automatic ignition advance. Unlike on the trend with the H1 these changes didn't drop performance.

1976 Z1[edit]

The model designation was changed to KZ900A and started in 1976 with the KZ900-A4 model.


Make Model Kawasaki Z1-A
Year 1974
Engine Type Four stroke, transverse four cylinder, DOHC, 2 valve per cylinder.
Displacement 903 cc / 55.1 cu-in
Bore X Stroke 66 x 66 mm
Cooling System Air cooled
Compression 8.5:1
Lubrication Wet sump, trachoid pump
Air Filtration Treated synthetic fiber
Induction 4 x 28mm Mikuni VM28SC
Ignition Battery and coil
Starting Electric & kick
Max Power 82 hp / 59.8 kW @ 8500 rpm
Max Torque 73.5 Nm / 54.3 lb-ft @ 7000 rpm
Clutch Wet, multi-plate
Transmission 5 Speed
Final Drive Chain
Primary Drive Straight cut gears
Gear Ratio 1st 12.79:1 2nd 8.84:1 3rd 6.74:1 4th 5.58:1 5th 4.92:1
Frame Double tubular steel cradle
Front Suspension 36mm Telescopic forks
Rear Suspension Dual shock, 5-way preload adjustment
Front Brakes Single 296mm disc 2 piston caliper
Rear Brakes 200mm drum
Front Tire 3.25 H19
Rear Tire 4.00 S18
Rake 27º
Trail 3.75 in.
Dimensions Length 2209.8 mm / 87.0 in.
Wheelbase 1498.6 mm / 59.0 in
Handlebar Width 818 mm / 32.2 in.
Seat Height 812.8 mm / 32.0 in.
Ground Clearance 170 mm / 6.75 in.
Dry Weight 230 kg / 507 lbs
Wet Weight 247.6 lbs / 546 lbs
Fuel Capacity 18 Liters / 4.7 gal
Consumption Average 48 mpg
Braking Distance 30 Mph - 0 29.00 ft.
Braking Distance 60 Mph - 0 126.00 ft.
Acceleration 0-30 Mph 2.7 sec
Acceleration 0-60 Mph 4.8 sec
Standing ¼ Mile 12.3 sec / 112 mph
Top Speed 135 mph

In Media[edit]

External Links[edit]