I may be not understanding..
What you wrote sounded like it measures the level of the oil, but the link shows a pump or vacumn extractor..
My thinking still is that when you are servicing forks, (moreso ones that are leaking).. the old amount is not a reliable guage as to recommended capacity..
So are you saying you dont drain out of the bottom? and stuff stays there??
It is a combination measuring stick and extractor, for sucking out excess oil.
I would agree the level is not a good gauge for the amount that should be in the fork unless you already know the appropriate measuring spot for that model, and for the CB750 I don't know. I've only done complete teardowns recently.
When I was riding my NT650 hawk at trackdays a few years ago, the suspension gurus said to ALWAYS measure, never drain and fill. That fork I had setup for me and they measured it as the correct height is well known in those circles. I had them add cartreidge emulators and Progressive springs (which use heavier wire and tighter coils) so the mass in the tube was greater and to simply fill with the recommended amount would result in overfill and poor performance.
And finally, yes if one simply drains out the drain hole, even pumping, there is a large amount of oil that will stick to the parts. So drain and fill will almost surely result in overfill. Only upon teardown and cleaning should one use the recommended amount to refill. Anything else is a best guess and may not be equal on both sides.
If one already has the fork back together, the tool can be used first to see that the levels are equal in both tubes, and then experiment in small increments.
This thread furthers the argument and gets rather heated, so I respect both sides, but advance the measuring argument.
http://www.t595.net/messageboard/thread/Fork-oil/23868.aspxThe tool can be replicated with a syringe and plastic tubing.
