I haven't tried this but it might work.  Take piece of small fuel line and run it from one vent to the other passing under the tank,  Make a small hole in the fuel line under the tank.  Not my original idea.

Larry, thanks I had actually forgotten about that method! I had tried it myself years ago  and while the idea of course is perfectly sound, I could not make it work for me because  I guess I had the wrong kind of tubing. All I had available to me then was the Perfect brand for which I was perfectly happy with except to do this particular modification.
My problem was that the tubing would not stay on the nipple. That is unless you made it rediculessly (sp) long. Then it just got in the way of everything and looked dorky.

Keep in mind that I was just a kid then and had not thought of maybe heating the tubing in hot water to help shape it (the Perfect brand was pretty stiff in cooler weather). That may have been what I needed to do.

I do remember (now) that I had bought a whole two feet of this tubing thinking that would be plenty and before I was done I had it all in a bunch of odd size pieces and it would be a month or more before I could get back to the LHS.  The tubing of course did not go to waste but I was pretty bummed out with my efforts.

The "U" shaped brass tubing I mentioned must have come from those old supressed memories trying to aleviate the side pressure of the fuel tubing. Keep it straight and it won't twist off.

I don't recall ever putting the vent hole in any of those pieces that I tried...  Could be I didn't want to poke a hole in an otherwise perfectly good piece of fuel line unless it would stay like it should.
 
Robert 

 

Here's the simple way.  Forget the integral tank, it's too small anyhow.

This is an .020 PeeWee but would work as well on a Babe Bee.

--Ray

Yeah, looks nasty, doesn't it?  It's balsa sanding dust.  I forgot the thing was sitting there and didn't cover the engine while sanding something else. I shoulda cleaned it up before I shot the picture but remember it is an .020, that's a real close closeup, in normal vision you can hardly see any dust on it.  See the "normal vision" below, shot at the same time.

I like that, "destroy the integrity of the tank".  Seems like I got that tank from you, didn't I?  With the hole already in it?  Anyway, I felt the same way at first but the stock tanks are pretty much worthless when you think about it, too small for more than a couple minutes' run, won't feed well inverted, tend to leak...butcher 'em, I say!  Since I was shown the above integrity-less fuel system works, I'm a True Believer.

--Ray