Did you look through the engine material on Kubotabooks.com?
Books
Kubotabooks.com in the "Tractor Owners Manual" section has a complete WSM for a B6000 with a ZL600 engine.
The copy is not great.
I have twice bought $9.95 instant download manuals from this site.
In one instance I was not happy, notified them immediately and my money was refunded.
Manuals
Using your credit card on line is just one of those risks you need to accept. Of course you need to be cautious.
Did you know this fact about B6000 provided by tractordata.com
The Kubota B6000 has a counter-clockwise PTO shaft, which is opposite the common direction.
I mention this so you do not spend a lot of money on engine repairs and then have problems using the PTO
Dave