2003 KFX400 Gas Overflowing Into Gearbox and Airbox

[Just-AC]

Okay, I'm sure you'll are saying "not this question again," but it's a little different.  As I stated in the title, my carb keeps overflowing with fuel and it the gas is going into my gear case and air box.  The float bowl doesn't have an overflow drain.  Stupid design, I know...  I didn't design it.  I replaced the float valve and needle twice and it hasn't changed.  I adjusted the float to where I would barely touch it and the gas will quit flowing.  When I say barely touch the float, I mean I BARELY TOUCHED THE STINKING FLOAT. As soon as I put it all together, I come out an out later and I have gas in my air box and gearbox.  I can't find anything obstructing the floats either.  Could I have gotten two bad valves and needles?  Then again, it shut off as soon as I touch the float.  I swapped the petcock out for the Raptor 660 petcock, but this problem was going on since before that swap.  Any idea what it could be, or did I just get 2 bad float valves and/or float needles?

To give you an idea on my mechanical skills, between my wife and 2 kids, we have about dirt bikes, quads, and a buggy.  I maintain all of them and have rebuilt 4 of them.  I am a certified motorcycle mechanic (I was certified in 1991, so it's been awhile) and I am a Master certified in automotive electronics.  I am extremely mechanically inclined and I know my way around a motorcycle.

[Jwbunton]

I have a 2004 DVX 400 and it was doing the same thing.  I had to replace the petcock because mine was basically just allowing it to prime all the time and overflowing anytime I was stopped.  Although I believe my carb has an overflow because it was running out the hose and not backfilling into the airbox.  

The new petcock seemed to fix the issue.  I did go with the OEM vacuum style petcock though.