TOPIC:

On the gpz900r , wet sump as other kz engines, the oil level is not simply as it should.
A moment after the engine is not running the sight glass its full over the max mark. Then it settle, or maybe not. And the level do whatever it want.
There is some air trapped in the system? There is a noreturn valve that not allow the oil to go in the sump in a reasonable time after shutting the engine off?
I drained it, i change the filter, now after ONLY 2 LITRES the sight glass is full. So i cranked it to fill the oil filter and prime the system. Oil light goes off.
After 10 minutes i add only 200cc of oil and im at the max mark again. How its possible the engine takr only 2,2 litres of oil?

I put my Kawasaki's on the same spot in the garage to check oil in the sight glass. I've found things are not always as level as they should be or as one would think. I can get different reading in different places in my garage so I selected one place. I might not get a 100 % accurate reading but as long as there is oil above the low oil mark all is good. Typically I don't have to add oil in between oil changes on either bike so I try to make the initial fill the best I can.

are you remembering there are 2 drain plugs on a 900r motor,at least i think there is ,it was over 25 years since i had one......

The owners manual did not mention about a second drain..

Mine was a GPZ 900r a2,i'm fairly sure there was a second drain plug at the bottom nearer the front of the motor,because i kicked myself a few times forgetting about it when i changed the oil,another 3/4 of a litre would come out,might still have the factory manual at home,i'll check and let you know.

I used to ride a first generation Concours that had essentially the same engine. Yes, there are two drain plugs. Also, as you stated, the oil level shortly after you stop the engine will read ridiculously high, but if you let it sit for a few hours, it will come down and give you a more accurate reading. I generally paid no attention to the oil level in the sight glass unless the bike had been sitting overnight. I have no idea why this was the case.

i was actually right!!!!! funny i couldn't remember when i got married ,but i remember this ,the brain is a funny thing....sorry they are showing upsidedown.