1973 Z1 900 Super 4
Frame Number Range: Z1F-00001 to Z1F-20000
Engine Number Range: Z1E 00001 to Z1E 20000
Frame Number Range: Z1F-00001 to Z1F-20000
Engine Number Range: Z1E 00001 to Z1E 20000
Z1's produced in August 1972 have matching frame & engine numbers.
All other Z1's have a close Frame/Engine Number range, this range was anywhere within 250 apart
All engine & frame production used a sequential numbering system from 1 to 20,000
Engines were time consuming to build, frames were not, thus frames have a lower number than the engine
Frames were ready & waiting for the engines to be placed in on the assembly line.
All engine & frame production used a sequential numbering system from 1 to 20,000
Engines were time consuming to build, frames were not, thus frames have a lower number than the engine
Frames were ready & waiting for the engines to be placed in on the assembly line.
All Z1 Engine Numbers are stamped on a 65mm by 14mm raised platform on right side of engine.
All Z1 engines were painted black with polished aluminum fins and covers.
Kawasaki received some complaints black paint would start peeling off the engine within months of buying.
All Z1 engines were painted black with polished aluminum fins and covers.
Kawasaki received some complaints black paint would start peeling off the engine within months of buying.
Frame number is stamped on left side of headstock.
On the right side is the same number printed on the manufacturers conformity sticker required for US imports.
It has info including the date of manufacture. First number is the month, second two numbers are the year.
This date on the sticker is when it was actually made not when it was exported, imported or sold.
The original sticker never will come off completly unless intentionally removed.
On the right side is the same number printed on the manufacturers conformity sticker required for US imports.
It has info including the date of manufacture. First number is the month, second two numbers are the year.
This date on the sticker is when it was actually made not when it was exported, imported or sold.
The original sticker never will come off completly unless intentionally removed.
The Z1 colors: Orange on Brown or Yellow on Green (only available in Europe).
USA only received Orange on Brown, Europe had both colors.
Official color names: Candytone Brown or Candytone Green. Kawasaki made no mention of Orange or Yellow.
USA only received Orange on Brown, Europe had both colors.
Official color names: Candytone Brown or Candytone Green. Kawasaki made no mention of Orange or Yellow.
Z1 Speedometer & Tach have a wide gap between words mph ND, (NIPPON DENSO) company that made them
(The Z1A has a close space between mph ND & x1000rpm ND)
(The Z1A has a close space between mph ND & x1000rpm ND)
Lights order NEUT FLASH BEAM OIL
The tachometer font of the 7 changed later in production of the Z1. Straight 7 was used first, later a curved 7.
The Position of the speedometer marker at the 20 mph also changed later in Z1 production.
The Position of the speedometer marker at the 20 mph also changed later in Z1 production.
Carburetors were Mikuni VM28SC. Carbs would be marked 1470 or 147 with 2 or 3 under the 147
Choke Lever has a black cap. The ON and arrow highlighted in red paint.
Choke Lever has a black cap. The ON and arrow highlighted in red paint.
Z1 has 155mm long Kawasaki Tank Badges (122mm between the screws)
Rear brake lining had NO wear indicator. All Z1A & Z1B had the wear indicator.
The last few thousand Z1 produced would have the updated casting as supply ran out.
These would however have no useable range decal and the indicator arrow was not present.
The last few thousand Z1 produced would have the updated casting as supply ran out.
These would however have no useable range decal and the indicator arrow was not present.
No gear change pattern (1-N-2-3-4-5) embossed on the chain case cover near gear shifter.
The last few thousand Z1 produced would have the updated casting as supply of the old cover was exhausted.
The last few thousand Z1 produced would have the updated casting as supply of the old cover was exhausted.
Z1 & Z1A used a chain oiler, Z1B did not. The chain oil tank is located under the left side cover.
Z1 used two style labels. Earlier being without the SAE 90.
Z1 used two style labels. Earlier being without the SAE 90.
The drain cap on the bottom of the tank changed from white to black plastic. White being first used.
Z1 reservoir cap has "BRAKE FLUID" cast into the metal.
Z1 Tail section document tray has two variations, the first used has NOTE & engine oil capacity is 3.7 Qt
Z1 Frame Does NOT have a hole in the sheetmetal below the tank. Any hole there would be a replacement frame.
The engine case has some subtle differences in the casting. For example the lower right of the engine case.
Just because the engine is painted black does not mean its a Z1
The cylinder head changed towards the end of the 1973 production model
Z1 Exhaust is chromed as a whole with no band around the muffler connection showing exposed weld
Bottom yolk has a hole in the casting on the underside that served no purpose and was eliminated soon into the Z1A production. This would appear on all Z1 and the first few months of Z1A production.
There were 2 versions of the cast aluminum Lower Front Fork legs.
Headlight brackets have smoothed seams before they were chromed, the Z1A has a visible seam.
The font brake caliper bolt has a hex star inside the mounting bolt.
Z1 used a different bleeder nipple & cap
2 different style petcocks were used. First ones used have aluminum instead of brass outlets for the fuel lines.
The lever was modified to add a o-ring due to stop potential fuel leakage.
The lever was modified to add a o-ring due to stop potential fuel leakage.
3 versions of the owners manual exist, with slight variations between them
One printed August 1972, November 1972 and March 1973
One printed August 1972, November 1972 and March 1973
The factory produced 4,846 Z1's August thru the end of December 1972, the remaining Z1 production was in January thru June 1973.
The Z1 was sold worldwide. Various countries had different regulations for motorcycle manufactures to comply with. Slight differences from country to country since Kawasaki had to conform the Z1 to specific regulations. Euro models featured a seat strap for a passenger to hold, Long rear fender, km/h speedo, fixed foot pegs, reflectors were not required and not used.
Z1 Specs: 903cc Engine, 82hp. Top speed over 125mph. 1/4 mile: 12 seconds. Weight 506 lbs.
Don't see a white sticker on your frame headstock?...You probably have a replacement frame.
Replacement frames do not have a white Identification sticker, you will see MADE IN JAPAN stamped in the metal.
If you remove the gas tank you might find the replacement part number tag affixed on the upper tube.
Faint impressions, crooked numbers, odd font and size, are all clear signs of a replacement frame.