Case number decide

I bought a 77 kz1000 title and vin match but on further inspection I noticed the cylinder jug is marked 903 so I'm assuming the engine has been replaced with a kz900 engine or z1 engine my question is how do I decode the case number to see what year and model this engine came out of this bike seems to be put together from several different bikes

You got a KZ900 motor (engine # Z1E 102602), Frame vin # for this model begins with Z!F 0xxxxx
and a 73 Z1 Candy Green/Yellow paint.

(K)Z900-A4 1976
Frame# Z1F-085701~
Engine# Z1E086001~

KZ1000
Frame# KZT00A0xxxxx
Engine# KZT00AE0xxxxx



www.kawa-z1.com/technics.shtml

www.kawa-z1.com/technics.shtml#database

Edit: Your sprocket cover belongs to the later 81 type of motor not the 73- 80 motor type you have.



a 77 kz1000

Thanks for the quick response the more I look at it the more I seem to have a bike made from several different bikes I've been doing a swingarm conversion and just keep noticing parts that don't seen to be correct for a 77 I do have the original paint but I like my 73 green and yellow lol