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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 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 Z1 and KZ900 owners can confidently distinguish original factory parts from aftermarket replacements, ensuring restoration accuracy, collector value, and historical authenticity for your prized 1970s Kawasaki bikes.

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 OEM rim production dates.
Kawasaki Z1 wheel rims by Takasago showing pre-1977 date codes with year/month format and post-1977 date codes after model code; Takasago model 303 rims for Z1 H1 and H2, 19-inch front, 18-inch rear
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 and KZ900 swing arm with date code markings; first number is year, next two numbers are month, some 1972 swing arms are unmarked

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 years 1972, 1973, 1974, 1975, and 1976

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
Kawasaki Mikuni Carburetor date code Info

Carbs
Carburetors were made by Mikuni. Model VM28SC. Z1's had 28mm carbs, 
Kawasaki carburetors were made by Mikuni. Z1s were equipped with 28mm model VM28SC carbs. Mikuni manufactured The 147 series and the 217 series. Initially the 1470 series was used, then 147 2 and 147 3. These were only used on the Z1 and Z1A.

The redesigned carbs were the 217 0, 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 KZ900 used 26mm VM26SS carbs.
​
Note: (1470, 147 2, 147 3, 217 0) refer to carburetor model numbers, not dates.
Z1 900 (903cc)
  • Carb size: 28mm
  • Carb series used: 1470 → 147 2 → 147 3 → 217 0
KZ900
  • Carb size: 26mm
  • Carb model: VM26SS​
Close-up of Kawasaki Z1 Mikuni carburetor showing 1470 date code marking on carbs
Kawasaki Z1 Mikuni carburetor showing 1473 date code markings on carbs
Kawasaki Z1 Mikuni carburetor showing 2170 date code marking on carbs
Kawasaki Z1 Mikuni carburetors showing 2Y date code carbs marking
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 carbs carburetor showing Kana character date code marking

Chain oiler
​Was also made by Mikuni and used the same Date Codes as the carbs.
Kawasaki Z1 chain oiler showing date code markings for years 1973, 1974, 1975
Kawasaki Z1 rotor showing date code part details

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 showing part details and date code marking
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

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
Kawasaki Z1 rotor showing part details and date code markings

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 Kawasaki Z1 12V regulator showing date code marking for 1974

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

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

Rear Wheel Hub
​ I
nk 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

Points Cover
​I
nk 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 genuine parts OEM points cover showing ink-stamped date code for 1974

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

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

Seat Foam
​ 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 seat pan foam showing part details genuine OEM NOS

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.

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 part details

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

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
Picture

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
Picture

Exhaust Mufflers were not dated until 1976. The 76 at the end of the markings is for the year.
Picture

Original factory paint colors for the 1973, 1974 & 1975 models were made as replacements to buy.
Z1 tanks made before the KZ900 have inner seams on the bottom, later have outer seams.
Picture

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.

Picture
Picture
Picture
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 damaged manual. 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.
Picture

A date code refers to the date a part was manufactured and not the motorcycle, parts were made before or just before the motorcycle (you cant make the bike without all the parts).

Since most all parts on a Kawasaki were sourced from other companies, you see different date code systems being used. Carbs were made by Mikuni, Rims: Takasago, Electronics: Nippon Denso, Coils: Kokusan, Tail light: Koito, Rectifier: Mitsubishi, Front breaking system: Tokico, etc...

The reign year system is what Japan traditionally used. It is based off the reign of the current emperor. Emperor "Showa" Hirohito reigned from 1926 until his death in 1989, so 1926 would be 1 and 1989 would be 64. Showa was the 124th Emperor of Japan and all Kawasaki motorcycles made to 1989 were manufactured during Showa's reign.

It is normal to see a date code for parts the same month a bike was made or a month or two before. Some months companies that supplied Kawasaki with parts had increased output and you see more rims for example made in May of 1975 because Takasago had maximum production that month. You will never see an original part made after the motorcycle, it obviously means the part was replaced. Parts wear from normal use or get damaged and replaced. Motorcycles are not rare baseball cards meant to be encapsulated in plastic cases never to be touched again by the human hand. They are meant to be used so parts naturally wear out. A rim made in May 1973 works the same as a rim made in July of 1975. A part is a part as long as it works as intended. The point of caring about date codes is a modern concept for finicky 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.

​Trivia Notes:
Kawasaki gets its name from the company's founder Shozo Kawasaki. I
t was originally a shipyard. He died in 1912 long before they thought about making motorcycles.

Kawasaki's 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

1973 z1
1974 z1a
1975 z1b
Date Codes
H2 750

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