Well, I did wrench on the carbs yesterday...
Clean up the bowl, the float and float needle, of the offending carb. I spotted the floats of this carb was "lower" than the other, so I jiggle it a bit.
I got them all line up pretty good. Height measurement were out of specs, but then, The 3 others weren't leaking... right?
By the time I got to get the bowls back in, I saw a felt pen mark I did before dismantling the carbs, oh oh... That wasn't the leaking carb... I was working on the second one and my problem was with the third one...
Hahaha...
Re-cleaned the right one, needle wasn't bad looking, as far as I know.
Put everything back in, carbs, gas cables, choke cable, airbox, gas tank, I'm getting good at this!
All good, Let's put this petcock to the prime position to get these bowl full of gas...
gulp, gulp, gulp... gas is leaking from carb no 1....
Ok what now. Then I remmbered
80GS1000 advice about knocking on the bowl.
As I was knocking down on it, my daughter asked me "Dad, are you really trying to fix this by knocking on it?"
But.... It worked!
And carb number 3, isn't leaking any more...
I finally rode over 50 km and got back home without a new problem!!!
Gosh this feels good...
Thanks you guys for your help!