Thanks for the replies.
I found the culprit I think... I pulled the engine and fuel tank, checked the tank for air leaks again. It was fine, but I replaced the cap assembly anyway. I then tested all the fuel lines for leaks. Wa-la.. the intake feed line had a pin hole. Looks like the brass pipe may had made the damage. I sanded the brass blunt and free of barbs. I replaced all fuel lines. I hope this solves this problem.
The clunk in the fuel tank has flipped forward......Put plane tail down and shake it til you can hear clunk rattle......WIDBL
I did not rule this out either. See below.
And if that doesn't do it, ensure that the clunk doesn't hit the rear of the tank when
swinging through from upright to inverted. It should clear it by 1/16!QUOT!-1/8!QUOT! to be safe.
You might actually remove the tank and put it at every conceivable angle, to make double
sure it doesn't hit or hang at any point. It has to be freely mobile to fly wild and crazy
Edit... note that this is generally more of a problem on !QUOT!squared off!QUOT! tank designs.
The clunk did clear the tank like you said above. However it was very free to loop forward if it wanted to. I have had this happen after a hard landing or crash. I assembled the take intake clunk with a setup that MinnFlyer had posted a while back with a brass line in-between the intake line in the tank. This will solve that problem. I hope with the mods and replacements this problem is one of the past. I will find out Sat or Sun if it is fixed.
Thanks Again,
Keith