My 1986 GPX 750 is having some carb dramas. Float height required, please.?

Question

I've changed all the float needles, and two of the four carbs are still flooding badly. The only thing I can put it down to, is a float level drama. Can anyone help with the following questions? a) what height to set the floats?, and b) is the measurement to be taken with the carbs up-side-down, or right way up? Every other carb component is O.K. This bike has massive sentimental value, so just throwing it away, isn't an option. For it's sake, though. It's lucky there's not an active volcano close by !!!

Answer 1

I've never measured or used a float level gauge on any set of carbs I've worked on.
--Remove the float bowls.
--Tie up 3 floats with rubber bands (so you can work on one at a time without making a mess).
--I hold the carbs above an oil drain pan to catch the gas.
--Attach a fuel supply and turn it on.
--Lift the float by hand. The fuel should stop flowing when the float arm is pararllel with the carb/float bowl mating surface.
--Bend the metal tang that touches the float needle to adjust.
--Repeate on the other carbs.
--Put the carbs back together.
--Hold the carbs at the same angle as if they were mounted on the engine.
--Turn on the fuel to see if they leak. Maybe shake them around a little to simulate being on the bike while ridding.
--If they leak - re-adjust.
--If you're still having problems, remove that float bowl and fill it with gas while it's off the carbs.
--The drain screw might be leaking.
--I had a problem similar to that. The over flow tube had a crack in it. What a relief figuring that out!
--Look in the gas tank with a flash light. Any rust and that's what's causing the leak - rust blocking the needle.
Install an in-line fuel filter to correct that problem.

Answer 2

Go for 12.7-13mm float height and see what this does for you. measure from the gasket surface to the top of the float. Have you changed needles/seats? Do the pilot jest exist?