Sorry about that, that's in the members area of the site.
Here it is,
This is supposed to stop the vaccuum once the end is under water, but I'm happy for someone to prove me wrong about this!
Okay I'll give it a go
When the tubes go under water it stops atmospheric pressure from pushing on the fuel in the bowl. There is a lower than atmosphere pressure in the venturi. The fuel moves from the higher pressure in the fuel bowl to the lower pressure area in the venturi. The amount of fuel that moves is controlled by the different jets in the fuel circuits.
Keith
I'm fairly sure the DR's run the same carb as the 05-07 Husqvarnas, if so your carby should look more or less like this.
On each side of the carb there are breathers, that way it doesn't matter which side you drop the bike on the excess fuel will overflow from the lower side.
Looking at the pictures below and using my yet to be cleaned from the weekend Husqvarna as the example. The Husky has a T piece on each side of the carby with two hoses coming out of it that both originally went down to the bottom of the bike.
I took the one that was facing up from the T and ran it up and down the main tube like this.
This is where there was five tubes, one carby drain and four from the carby vents, after mod there is now only three.