TOPIC:

I have a Z1 900 Engine in a chopper frame, looks to be factory black but the Engine # is z1 e-23668

now I know this is too high as 20000 is supposed to be 1974 numbers, but I know the engines were generally 200 numbers ahead, but did that stretch out towards the end of 1973 Production?

www.kawasaki-z-classik.com/

You might want to check with the above folks (and you will have to join to post...it's free). They keep track of all those types of information dealing with the Z1 series.

Z1F-19998 HAS ENGINE Z1E-20032 (Z1A SILVER MOTOR)

Z1F-20033 HAS ENGINE Z1E-20053

At the end of the day they are all over the place, plus it's all speculation (unless someone comes up with build sheets) as these 2 bikes could of had engine swaps by KHI quality control or even the dealer in it's warranty period. (although very unlikely)

Over here in Bunbury WA, a near end of model Z1B (1974) owner has original sales receipt showing it was factory fitted with an very early A4 (1976) motor.