Easy way to empty a GS tank

By: AdvWisdom
Title: Easy way to empty a GS tank
Sourced From: advwisdom.com/a/easy-way-to-empty-a-gs-tank/
Published Date: Thu, 25 Jun 2020 15:25:14 +0000

Use the fuel pump to empty your GS tank

So I need to remove the fuel tank and as usual, I just filled up the tank. D’oh!

Make this handy fuel drain hose, and let the fuel pump empty the tank for you.

Also works for aerial refueling of another bike.


The fuel system continually recirculates the fuel. The fuel pump sends high pressure fuel to the regulator. And the regulator returns low pressure fuel to the tank. This method of empthing the tank simply intercepts the returning fuel. So instead of the fuel dumping back into the tank, it dumps into the gas can. The fuel system does not even know this is happening.

Start the engine and let the fuel pump drain the tank. Flow rate is slow, and low pressure. You can see in the picture above that the hose is staying in the gas can unattended. Smooth easy flow. A little stronger, but about what you’d expect from a good siphon.

Watch the fuel coming out of the end of the hose. Right after the fuel pump intake impeller begins to whine, the fuel flow will sputter. And you can shut off the engine. This is not an issue for the fuel pump.

At this point the tank has about 1 gallon remaining. If you have an Adventure tank with a crossover OR an S4 siphon crossover maybe about 1/4 gallon. johnjen’s S4 siphon crossover can be found here.

If your tank does not have a crossover, and you want to get most of the remaining fuel out, there is a way. Lean the bike over on its right side, for the best result, touch the cylinder to the ground. The remaining fuel will pour over the tank’s ‘internal saddle’ and into the right side lobe. The pouring fuel is clearly audible.

Reset the bike on the center stand, put the drain hose back into the gas can, and start the bike. About another gallon will pump out.

Or, just take the tank off with one gallon of gas in it. Only 6 pounds. That sure beats 36!