This reminds me, I'm due for my 2nd fork oil change...
Easy to do without needing to take the fork internals apart. Just the top cap and remove fork tube from triple. Measure what you take out, put back same. The right fork could be done for every 2x left fork change....but one oil container is enough to do both forks so why not. I don't like to keep oil for a long time sitting on a shelf (once opened container).
This is what mine looked like at 12K miles (left leg):This is the new oil:This is the oil I used because its slightly thicker than what comes on Z900:
For more info, use the search option, me and other have made posts on here before.
Edit: forgot to mention, not all 5w oil is 5w...not all 7w is 7w. This is why the selection of oil I picked was very specific
due to other specs.