2007 panther 110cc

I have cleaned at least 3 different carbs and installed them in this same atv numerous times with the same end result,they all leak gas from the overflow.
I went so far as order a rebuild kit and it still leaks gas.
I can take it off and put it on another atv and it will not leak gas.
the only thing I see different is the drain plug hits the intake. I have numerous carbs/intakes but can't seem to find 1 that will stay away from the intake.Not sure what that has to do with the constant leaking but it is different than the other atvs.
longest I had it to go without leaking is 2 days.
I have worked on numerous of these Chinese atvs and this 1 is the only one that will leak. I cleaned 2 carbs yesterday,re-installed and both carbs are working perfectly.
this has been going on for a week now.I would say the carbs have been off and on at least 30 times in some configuration. I have swapped parts with each carb trying to find exactly what is wrong.
any suggestions?

 

You might check the float pivot holes. I have found that when new, they don't
always swing freely on these Chinese carbs. If the installation on one of the ATVs
has the carb a bit out of level, the poor-performing float can cause trouble.

With new Chinese carbs, I never install them before a full rebuild and QC check.

 

pic's?