Uhhhh ..... that gizmos is not used to REMOVE ALL the fork oil...and it can't!
That gizmo is used to get the correct fork OIL LEVEL.....you slightly OVERFILL the fork...then you set the probe to the correct air gap depth, and SUCK....presto..the perfect oil level.
The only way to get the oil out is to remove the fork leg, dump...pump, dump... pump etc...then invert and let drain for a spell....and even then there will be a slight amount of oil left in there....
This is why you use that gizmo....you can't refill accurately by VOLUME since you don't know how much residual oil is in there...but with the gizmo you refill by height = perfect oil level.
If you wanted to get out ALL of the oil, it would require disassembly of every single part and piece of the fork mechanism...and cleaning of that...
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