KAWASAKI Z1 900, KZ900, H2 750 & H1 VINTAGE DATE CODES – COMPLETE OEM PARTS GUIDE

This Kawasaki Z1 900, KZ1000, H2 mach IV, and H1 500 parts date code guide is designed for classic Kawasaki collectors, vintage motorcycle restorers, and Z-1 & KZ900 owners. It provides detailed date codes for 1970s Kawasaki motorcycles, covering every key genuine OEM part.
Whether you are restoring a vintage Z1, KZ1000, H2, H1, or 500/750/900 Kawasaki, this guide shows you how to accurately identify genuine Kawasaki parts, verify original production dates, and confirm authenticity with this kawguy.com date code markings reference data. From year and month codes to ink-stamped dates on NOS parts, every part is covered to help you restore or maintain your classic Kawasaki motorcycle to original factory specifications.
With this guide, Kawasaki 900Z1 and KZ900 owners can confidently distinguish original factory parts from aftermarket replacements, ensuring restoration accuracy, collector value, and historical authenticity for your classic 1970s Kawasaki bikes.

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Kawasaki Takasago Wheel Rims – Date Code Guide

Wheel rims for Kawasaki Z1, KZ900, H1, and H2 models were manufactured by Takasago. These rims include date code markings to identify their production year and month.
Pre-1977 Rims:

• Format: Year (number) / Month (letter)
• The Number represents the year and the letter represents the month
• Year codes: 2 = 1972, 3 = 1973, 4 = 1974, 5 = 1975
• Month codes: A = Jan, B = Feb, C = Mar, D = Apr, E = May, F = Jun, G = Jul, H = Aug, I = Sep, J = Oct, K = Nov, L = Dec

Post-1977 Rims:

• Date codes appear after the model number code
• Format: First two numbers = month, last two numbers = year

Model Numbers:

• Takasago used model number 303 for Kawasaki Z1, H1, and H2 rims. Model 305 was used for front dual discs brakes.
• Sizes: 19-inch front, 18-inch rear

These codes allow for precise verification of vintage rim OEM genuine parts production dates.

Kawasaki Z1 wheel rims by Takasago showing date codes. Model 303 rims fit Z1, H1, and H2 models—19-inch front and 18-inch rear.

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Kawasaki Z1/KZ900 Swing Arm Date Codes

​The swing arm on Kawasaki Z1 and KZ900 motorcycles includes date code markings to indicate the year and month of manufacture. The first number represents the year —3 for 1973, 4 for 1974, 5 for 1975, and 6 for 1976—while the next two numbers show the month in two-digit format, with 01 for January through 12 for December.
​Some swing arms manufactured in 1972 do not have any markings.

Kawasaki Z1 & KZ900 swing arm showing date code markings—first number indicates the year, the next numbers indicate the month

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Kawasaki Z1/KZ900 Rear Shocks Date Codes

The rear shocks on Kawasaki Z1 and KZ900 motorcycles include factory date code markings to indicate the year and month of manufacture. The first number represents the year: 2 = 1972, 3 = 1973, 4 = 1974, and 5 = 1975. The second character, which may be a number or letter, indicates the month. Single-digit months are shown as numbers (1 = January, 2 = February, 3 = March, 4 = April, 5 = May, 6 = June, 7 = July, 8 = August, 9 = September), while October, November, and December are represented by letters: O = October, N = November, D = December.
For two-digit months, the code uses the first letter of the month O = October, N = November, D = December. Use this kawguy.com reference guide to verify the authenticity and production date of genuine rear shocks.

Close-up of Kawasaki Z1 rear shocks showing date code markings for 1972, 1973, 1974, 1975, and 1976, useful for authentic part verification

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Kawasaki Z1/KZ900 Torque Arm Date Codes

The torque arm on Kawasaki Z1 and KZ900 motorcycles includes factory date code markings to indicate the year and month of manufacture. The first number is the year—3 = 1973, 4 = 1974, 5 = 1975—while the second number is the month, 1 = January through 12 = December. Some torque arms manufactured in 1972 may not have any markings.

Kawasaki Z1 torque arm showing date code markings for years 1973, 1974, 1975, and 1976

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Kawasaki Mikuni Carburetor date code Info

Kawasaki carburetors were made by Mikuni. Z1s were equipped with 28mm model VM28SC carbs. Mikuni manufactured The 147 series and the 217 series. The first carbs used were the 1470 series. The carbs were updated to the 147 2 and 147 3. The "1470 - 1473" series were only used on the Z1 and Z1A.

The redesigned carbs were the 217 0. These were used on late Z1A and all Z1B Models. According to a Kawasaki bulletin, 217 series carburetors were specified to be fitted on engines numbered 32866 and higher. The 2170 Mikuni carburetors were used to the end of production and available as genuine replacement parts to be purchased from dealers.
The KZ900 used completely different Mikuni 26mm VM26SS carbs.
​Note: (1470, 147 2, 147 3, 217 0) refer to carburetor model numbers, not dates.

All Z1 900 Carburetors were made by Mikuni. Model VM28SC. Z1's 28mm carbs; KZ900 26mm carbs.

Z1 900 (903cc)

• Carb size: 28mm
• Carb model: VM28SC
• Carb series used: 1470 → 147 2 → 147 3 → 217 0

KZ900

• Carb size: 26mm
• Carb model: VM26SS​

Detailed view of the 28mm Mikuni carburetors from a 1973 Kawasaki Z1 900, 1470 series were the first carbs used on the Z-1

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Original Kawasaki Z1 Mikuni carburetors 1473 revised series, used to verify correct period parts this is not a date code

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Close-up of a 28mm Kawasaki Z1 Mikuni 2170 series carburetors, useful for identifying correct year and model carbs

Kawasaki Z1 date code stamp on Mikuni carburetors—what they mean and how codes help identify the correct production year and month

Where are the date codes on Kawasaki Z1 Carbs?

Carbs can be dated to the year and month. They are marked on the left side of the carbs.
​The first Number represents the year: 2 (1972), 3 (1973), 4 (1974), 5 (1975) 
Second number or letter is month. 1 Jan, 2 Feb, 3 Mar, 4 Apr, 5 May, 6 June, 7 July, 8 Aug, 9 Sept, X Oct, Y Nov, Z Dec (Two-digit months use letter)
​Note: August & September 1972 used Japanese Kana characters as a date.

Kawasaki Z1 Mikuni carburetor date code example, highlighting how to read year and month stamps for accurate parts verification

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Chain oiler
The Mikuni chain oiler, used exclusively on the 1973 Kawasaki Z1 and 1974 Z1A, features the same date codes as the carburetors.

Mikuni chain oiler for the 1973 Kawasaki Z1 and 1974 Z1A, featuring the same date codes as the carburetors for accurate vintage motorcycle part identification

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Kawasaki Z1 chain oiler showing date code markings for 1972

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Brake Disc
This number is in "Showa Date" form, with the first number of the reign year dropped. This is a reign date system Japan traditionally used. Emperor "Showa" Hirohito reigned from 1926 until his death in 1989. 1926 would be 1, 1989 would be 64. 47 = 1972, 48 = 1973, 49 = 1974, 50 = 1975, 51 = 1976. Now if thats not complicated enough the second letter represented not month but 4 weeks. There were 13 letters used to cover 52 weeks, A to V was used.
This rotor 0B was made week 5-8 of 1975. It's simple once you understand the unusual system.

Kawasaki Z1 disc brake with visible date code, useful for verifying authentic genuine OEM parts

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Z1 Speedometer and Tachometer made by Nippon Denso

Speedometer & Tach are dated to the exact day. Stamped on the back in red ink in Showa format.
Reign year (47=1972, 48=1973, 49=1974, 50=1975) / month / day

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Brake Rotor
The first Number represents the year: 2 (1972), 3 (1973), 4 (1974), 5 (1975)
The second letter is month A JAN, B FEB, C MAR, D APR, E May, F June, G July, H AUG, I SEP, J OCT, K NOV, L DEC

Close-up of a Kawasaki Z1 rotor showing part details and date code markings for accurate model year identification

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12V Regulator
​ The first Number is year: 2 (1972), 3 (1973), 4 (1974) 5 (1975)
Second letter is month A JAN, B FEB, C MAR, D APR, E May, F June, G July, H AUG, I SEPT, J OCT, K NOV, L DEC
The third number that follows the letter does not matter.

Close-up of a Kawasaki Z1 12V regulator showing the date code for accurate 900 motorcycle part identification

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Break Shoes
​ Ink stamped with the date they were made.
The first number is in "Showa Date" form (47=1972, 48=1973, 49=1974, 50=1975). Second number month. third day.

Kawasaki Z1 brake shoes showing ink-stamped date code markings, identification of year manufactured

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Starter Solenoid
​ Ink stamped year / month
The first Number (one number) is the year: 2 (1972), 3 (1973), 4 (1974) 5 (1975)
Second two numbers are Month. 01 Jan to 12 Dec

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Rear Wheel Hub
​ Ink stamped with the exact day they were made.
The first number in "Showa Date" (47=1972, 48=1973, 49=1974, 50=1975), Second number month, third number day.

Kawasaki Z1 rear wheel hub showing ink-stamped date code with exact manufacture day

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Points Cover
​Ink stamped with the exact day they were made.
The first number in "Showa Date" (47=1972, 48=1973, 49=1974, 50=1975), Second number month, third number day.

Kawasaki 900 & 1000 genuine parts OEM points cover showing ink-stamped date code for 1978 KZ1000 not Z1

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Clutch Plate
​ ​Ink stamped inside near center with the exact day they were made.
The first number is in "Showa Date" form (47=1972, 48=1973, 49=1974, 50=1975), Second number month, third day.

Kawasaki Z1 clutch plate showing date code markings NOS genuine OEM parts

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Sprocket Carrier
​ Ink stamped with the exact day they were made.
The first number is in "Showa Date" form (47=1972, 48=1973, 49=1974, 50=1975), Second number month, third day.

Kawasaki Z1 sprocket carrier showing date code markings NOS genuine parts

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Seat Foam Padding
​ Ink stamped with the exact day they were made.
The first number is in "Showa Date" form (47=1972, 48=1973, 49=1974, 50=1975 52=1976), Second number month, third day.

Kawasaki Z1 & KZ900 seat pan foam showing a genuine OEM component date coded in ink

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Ignition Switch and Seat Lock (located on the side of barrel)
The first Number represents the year: 2 (1972), 3 (1973), 4 (1974) 5 (1975)
Second number or letter is the month in 1 digit format. 1 JAN, 2 FEB, 3 March, 4 April, 5 May, 6 June, 7 July, 8 AUG, 9 SEPT, O OCT, N NOV, D December. One number format meant two digit months use first letter of month.

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Switch Blocks are marked on the bottom half (visible when grip removed)
First Number is the year: 3 (1973), 4 (1974) 5 (1975). Second numbers are the month

Kawasaki Z1 handlebars switch block electronics showing date code part details

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Brake lever & Clutch levers

Brake and Clutch levers starting in 1975 were marked on the bottom cast in a circle. 
The first Number is the year: 5 (1975) 6 (1976)
Second letter month A JAN, B FEB, C March, D April, E May, F June, G July, H AUG, I SEPT, J OCT, K NOV, L DEC

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Kawasaki Z1 Lower Fork Yolk

Bottom front fork yolk has a 2 digit date code first number year second number month.
2 (1972), 3 (1973), 4 (1974) 5 (1975) Second number month 1-12 Jan-Dec

Close-up of the Kawasaki Z1 bottom front fork yolk with 2-digit date code, helping verify authentic vintage parts.

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Tail light bracket
​First Number year: 2 (1972) 3 (1973) 4 (1974) 5 (1975)
Second number or letter is month. (1-9 JAN-SEPT) X OCT, Y NOV, Z DEC

Kawasaki Z1 tall light bracket showing date code markings, used to identify the correct production year and month for genuine parts

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Genuine kawasaki z1 & kz900 original exhaust system mufflers

Exhaust mufflers were not dated until 1976. The “76” at the end of the markings indicates the year. Exhaust pipes continued to be produced as replacement parts available from dealers. All replacement parts made there after were stamped with “76”, and the year was never updated, so you won’t find 77, 78, or later--“76” became the permanent marking.

Genuine Kawasaki Z1 and KZ900 original exhaust system mufflers showing date codes for authentic part verification

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Z1 vs. KZ900 - How to Tell the Difference Between Z1 & KZ900 Gas Tank

Original factory paint colors for the 1973, 1974, and 1975 Kawasaki Z1 Fuel Tanks were also made as replacement parts available for purchase. Z1 fuel tanks made before the KZ900 have inner seams on the bottom, while later KZ900 gas tanks feature outer seams.

Original Kawasaki Z1 factory paint colors for 1973–1975, available as replacement parts. Z1 tanks made before the KZ900 have inner bottom seams, while later KZ900 tanks have outer seams for verification

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NOS Genuine Kawasaki Part Number Labels

From 1973 Kawasaki replacement part labels are dated under Q'TY (Number Letter) Number is year (3) 73, (4) 74..etc, letter is month (A) January...etc. Starting in 1980 labels will have the Big K, same date code principle. 
​Barcodes started in 1990.

NOS genuine Kawasaki part number labels, showing original markings for authentic vintage motorcycle parts verification

Close-up of NOS Kawasaki part number labels, highlighting original markings to confirm genuine vintage parts

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Original Kawasaki Z1 & KZ900 owners manual

Owner's manuals are dated to the month and year just like any normal book. Several versions of each manual were made with revisions. Most owners stored manuals in the tail section compartment often resulting in a water damage. Manuals could be purchased as a replacement part, those are originals not reproductions. Reproductions are distinguishable from the real thing, even the highest quality ones.

Original Kawasaki Z1 and KZ900 owners manuals, a genuine vintage copy for authentic model reference

Kawasaki datę codes chart showing years for identification on genuine parts

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Where do I find kawasaki Date Codes on a z1 motorcycle?

A date code refers to the manufacturing date of a part, not the motorcycle itself. Parts were produced months before or just prior to assembly, since a bike cannot be built without all its components. Understanding this distinction is essential for restorers and collectors.
Because most Kawasaki motorcycle parts were sourced from external suppliers, multiple date code systems exist. For example the following parts were made by the following companies for Kawasaki:

• Carburetors: Mikuni
• Rims: Takasago
• Electronics: Nippon Denso
• Coils: Kokusan
• Tail lights: Koito
• Rectifiers: Mitsubishi
• Front braking system: Tokico

Each supplier had its own manufacturing process and date coding method, so it’s common to see parts with different date codes on the same motorcycle. You will never see an original part made after the date the motorcycle was made. That would obviously indicate the part is replaced.

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Understanding Kawasaki Motorcycle Parts Date Codes Showa Era Reign Years

Japan traditionally used a reign-year system for dating, based on the years of the current emperor’s rule. For example, Emperor Showa (Hirohito) reigned from 1926 until his death in 1989. In this system, 1926 is Year 1 of Showa, and 1989 is Year 64. Showa was the 124th Emperor of Japan, and all Kawasaki motorcycles produced up to 1989 were made during the "Showa" reign.

• Emperor Showa (Hirohito) reigned from 1926 to 1989.
• 1926 = Year 1, 1989 = Year 64.
• All Kawasaki motorcycles made before 1989 were produced during Showa’s reign.

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Why Date Codes matter restoring a z1 motorcycle

It is normal to see a date code on a part from the same month as the bike’s manufacture or a month or two earlier. Some suppliers ramped up production in certain months, so you might see, for instance, more rims stamped May 1975 because Takasago was producing at full capacity that month.
The date on the Motorcycles VIN tag is the month the motorcycle was started on the assembly line. The finished identification tag was placed on the bike before assembly. A tag dated 3/74 means the bike started being made 3/74. If the bike was started last day of March 1974 and finished on the next shift April 1st 1974, the tag would still be march and not changed to April.
Any part dated after the bike was made is obviously a replacement part. Motorcycles are meant to be used, not preserved like rare collectibles. Parts wear out or get damaged over time, and replacements are a normal part of ownership.
A rim made in May 1973 performs just as well as one from July 1975. Functionality matters—parts are parts, as long as they work as intended. The point of caring about date codes is a modern concept for collectors who must have perfection when completing their restoration. To most it seems a silly thing to care about but to the most passionate collector it makes a difference.

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Date Codes and Restoration: A Collector’s Perspective

Caring about date codes is largely a modern collector concern, often tied to a desire for perfection in restoration. To many riders, it seems trivial, but to dedicated Kawasaki restoration enthusiasts, matching parts by date can make a significant difference for a die hard collector. 
In short: date codes are a tool for verification and restoration accuracy reference, not a requirement for usability. Motorcycles are meant to be ridden and enjoyed, so parts naturally wear out. Date codes are a tool for collectors, not a requirement for functionality.

Where did Kawasaki get its name from?
Kawasaki gets its name from the company's founder Shozo Kawasaki.

Did Kawasaki always make motorcycles?
No. It was originally a shipyard. The companies founder died in 1912 long before they thought about making motorcycles.

What year was Kawasaki founded?
1878 as Kawasaki shipyard in Tokyo, Japan.

How did Kawasaki Z1 motorcycles get imported to the USA?
Kawasakis were imported thru their US distributors:
Kawasaki Motor Corp.                     Kawasaki Motors
​1062 McGraw Ave.                            No. 3 Production Way
Santa Ana, CA 92705                        Avenel, NJ 07001
​​If you have an estate to liquidate or non Kawasaki motorcycles here are websites that might be able to help you. https://www.weekendestatesales.com/  https://www.wantedoldmotorcycles.com/
Kawasaki's were imported thru their UK distributor:
Kawasaki U.K. Ltd
Radix House Central Trading Estate
Staines Middlesex, England

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1973 z1

1974 z1a

1975 z1b

Date Codes

H2 750