[Michael NinjaR]

It should be in the manual...mine says 91 recommended (min 87). Check again in the manual, otherwise do some google searching.

Like so: Google: "z1000 octane"

First result says 91...

"Z1000 min Octane Fuel
is 91 I was going threw my Owners's manual today looking for a exact # and found it on page 25 under emission control information.
so now we have a exact number we can use so if the dealer ever asks what kind of fuel your using say super "

 

[Michael NinjaR]

Noo prob =] google is your friend when you need to know just about anything =p