All Z1 & Z900 frame numbers are stamped on the steering head. Additionally, in the USA & Canadian market, there is a white sticker on the steering head showing the frame number and the date of manufacture. This date of course can be many months before the bike was actually registered, normally around 2-3 months.
The frame numbers will be in the following ranges
Z1F-00001 through Z1F-19999
Z1F-20000 through Z1F-47499
Z1F-47500 through Z1F-85700
Z1F-85701 through Z1F-138846 for bikes manufactured in Japan
Z1F-500001 through Z1F-510340 for bikes assembled in Lincoln Nebraska
THE KZ900 LTD FRAME NUMBERS RAN FROM KZ900B-500011 THROUGH 505514
Z1 & Z900 engines have engine numbers stamped on the top right side crankcases on a raised area over the clutch.
The engine numbers follow the same general range as the frame numbers although Frame and engine numbers were not matched at the factory.
Most bikes have the engine number higher than the frame number, but this is not always true.
While the frame and engine numbers are the best indication of the model and whether the engine has been replaced, these are not the only numbers to help validate an 'authentic' Z1.
Very early 1972/1973 models do not have the legend "KICKSTART" embossed on the crankcases and 1972/1973/1974 models have a horizontal casting mark on the front crankcases in front of the alternater cover.
On 1972/1973 models, the 903 CC legend on the front of the cylinder block is stamped onto a raised block, all models afterwards are stamped directely onto the barrel.
Confused????? Well read on!
On a number of Z1 components are date codes. For a bike assembled in June of 1973, it is reasonable to expect all of their parts to have been made in the current month (Jun 73), prior month (May 1973) or even two months back (April 1973). It is not reasonable for parts to have been made AFTER the build date. Yet on close inspection of numerous 'restored' bikes, it is obvious the restorer utilized factory replacement parts or parts from later models to replace marginal or damaged parts. While this is not always a problem, it will of course tell you if the bike in question is 100% original! Remember though that parts may have been changed under warranty at a later date unknown to the owner or indeed the restorer.
Swing arm codes
On the top right front of the swing arm, by the grease nipple, is a date code. This shows the date of manufacture for the swing arm. The code uses the format Y MM where the first number is the year and the other numbers are the 1 or 2-digit month. . For example: 3 12 is December 1973.
Rear Brake Torsion bar (chrome bar)
On the back of the chrome bar is a date code . The first number is the year and the second number the month, So 3 6 is June 1973.
Handlebar switch blocks
On each handlebar switch block is another date code showing the date of manufacture. When the switch block is removed from the handlebars, the code is on the outside of the case facing the handlebar grip. The code uses the format Y MM where the first number is the LAST digit of the year and the other numbers are the 1 or 2-digit month.
Chrome wheel rim
On each rim is yet another date code identifying the date of manufacture. This code uses the last number of the year and a letter to identify the month. A= January, B= February and so on. So 4D would be April 1974
Of course there were many more Date codes on other parts, follow this link to John Brooks Z2 site which explains them a lot better
1972/1973 SPEEDO:The 1972/1973 Z1 speedometer is identified by the following features. The numbering on the face is in 20 mph increments. The second is the ND (for Nippon Denso) on the face is very low down on the face - right at the very bottom. Lastly the speedometer goes up to 160 mph.
1972/1973 TACHO:Like the 1972/1973 Z1 speedometer, the tachometer has the same small ND very low on the face. The redline starts at 9,000rpm and finishes at 12,000rpm
1974 SPEEDO:At first glance, the 1974 Z1-A speedometer looks very much like the 1973 Z1 version. It is another 160mph speedometer with 20mph increments. One noticeable difference is the ND on the face has moved slightly higher while the MPH has moved much lower on the face.
1974 TACHO:The 1974 version of the tachometer changed to incorporate a red brake light warning light. This light would come on when the brake was applied, and would flash in warning if the brake light bulb failed. Similar to the corresponding 1974 Z1-A speedometer, the tachometer's x1000 rpm lettering moved down the face while the ND moved up slightly. The redline remained at 9,000 rpm. PART NUMBER:25015-025
1975 SPEEDO:While still remaining a 160mph speedometer, the markings now showed the speed in 10mph increments. The ND and MPH letters remained in relatively the same place as the Z1-A gauge.
1975 TACHO:The 1975 Z1-B tacho is the same as the 1974 Z1-A model, no change. PART NUMBER:25015-025
1976 SPEEDO:Same as the 1975 Z1-B speedometer. No changes.
1976 TACHO:With the arrival of the Z900-A4, Kawasaki dropped the brake light warning light in the tachometer. The redline remains at 9,000rpm. So for this year, the tachometer looks similar to the 1973 gauge except for the position of the ND and x1000rpm on the face.
KAWASAKI: LET THE GOOD TIMES ROLL
Z1-900 COLOUR OPTIONS
CARB SETTING GUIDE
Z1 & early Z1-A
5J9-3 - last number is the clip position where 1 is at the top of the needle (leanest) and 5 is at the bottom (richest)