I picked up a service manual for the mighty YZ400F (1979) a while back and thought it should go to a good home (I am a suzook man myself).
YZ400F 1979 Model Guide/Service Manual - $70 plus Post (if outside Australia)
It is in great condition, has a few finger print marks on the front and back covers but the pages inside are un-marked.
I, and the manual, are based in Melbourne.
Send me a PM if you would like to read more about your pride and joy.