How to empty the fuel tank

[Donmystic1]

I need to remove my fuel tank from a naked 1985 K100.
It is full of fuel.
Can I disconnect one of the fuel lines and turn on the ignition so that the fuel pump runs and therefore pumps out the fuel into a gas jug?

[rbm]

I just dump the fuel.  Remove the tank, remove the fill lid, dump the fuel into a pan (I use my oil collection pan after cleaning it of any residual oil).  I pour the fuel from the pan into a gas can afterwards.  You can pretty much dump 99.9% of the fuel this way; the remainder in the tank you can wipe up with a paper towel.

[Donmystic1]

With a full tank of gas that weighs about 48 lbs that is a bit heavy to lift off the bike. I would like to drain off 75% first.

[rbm]

You won't be able to disconnect one fuel line and hope to pump out the fuel.  The fuel pump will run while the engine is cranking and for 1.5 seconds after it stops.  To crank the engine for the length of time it would take to pump the majority of gas out of a full tank could be damaging to the starter motor (potential starter overheat, and battery overheat).  The tank is heavy but not unwieldy. 

If your objective is strictly to remove a full tank to access under the tank, the process is straightforward.  The tank does become heavy but it's not unmanageable, even by one person alone.  I've done this many times myself.  If you fully disconnect the fuel lines and electrical connector, no fuel will leak out of the tank and it can be moved without worry of spillage, so long as it is kept upright.

If your objective is to work inside the tank, what I suggested earlier is also manageable, even by one person.  Being careful is absolutely paramount because of the open fuel, risk of spillage and potential fire hazard.

EDIT: Just throwing an idea out there.  You might be able to rig an external battery to drive the fuel pump through the tank connector, if you can find a reliable means to connect the two leads (+ve and -ve)  to the connector.  Then disconnect the fuel line at the fuel rail, direct it into a pail and run the pump from the external battery source.  The danger with this is the risk of fire due to sparking arising from trying to connect the battery to the connector.  Those sparks in the vicinity of fuel vapours is a fire hazard.

[Donmystic1]

Ok I have a remote Holly Fuel pump so I think that I will siphon most of the fuel out into a jug.

[K1300S]

I have a cheap electric fuel pump I use for draining tanks.  Connect to spare battery and pump into fuel can.

[technostructural]

I just siphoned it out with a 3/8 vinyl hose and a gas can. Make sure you tuck the hose in the deepest part of the tank (closest to the outer edge of the tank). There is a lip that goes down in there that is about an inch or two deeper than the rest of the tank. If you put the bike on the kickstand, it'd be even better because it will slosh to one side.

You may not get it all out this way, but the remainder shouldn't be too heavy to lift and dump or use a paper towel as mentioned above.

[Laitch]

I use one of these six buck syphons tucking the smooth hose down into the tank like techno describes in the post above. I drop the other hose into a plastic tank on a stool that's slightly lower than the bike's tank, squeeze that orange bulb with a salsa rhythm and away we go.

[TimTyler]

With a full tank of gas that weighs about 48 lbs that is a bit heavy to lift off the bike. I would like to drain off 75% first.

If you've got enough upper body strength to ride a K, you can lift a full fuel tank off. It's definitely not worth trying to drain it if the fuel is not contaminated.

You're right - it is heavy though.

[RobP]

Ditto on the siphoning.  I just used a long piece of translucent 1/4" tubing that was long enough to see the gas long before it hit my mouth.  Not usually a fan of that approach, but it was simple and effective.

[Donmystic1]

I didn't mention but I am changing the color of the tank and the painter needs it to be empty.

[Laitch]

I knew you had a good reason, Don. I'm the only person I know who empties the tank just for fun.

[buddymack]

Dude!  When did we loose the basic ability to siphon fuel out of a tank 3 ft in the air? 

[johnny]

empties the tank for fun... that would be between 5 and 8 thou on the tach for me...

[Donmystic1]

Remember that my initial question was, Can I use the electric fuel pump to empty the tank ?

The consensus is that you have to siphon the fuel from the tank using an external hose.

Thanks all for your help. I am converting a "Naked K" with only 13,000 miles to a K100RT.

Then I'll have a 1985 K100RS with 9,000 miles, a 1986 K100RS TUrbo ( number 3 of 20 made ) and the K100 RT.

[johnny]

rodger that donmystic1...

my method does in fact use the electric fuel pump to empty the tank...

keep it going... post up some photos along the way...

j o

[Laitch]

empties the tank for fun... that would be between 5 and 8 thou on the tach for me...

220 miles on the road for me.

[Texer]

I use one of these six buck syphons tucking the smooth hose down into the tank like techno describes in the post above. I drop the other hose into a plastic tank on a stool that's slightly lower than the bike's tank, squeeze that orange bulb with a salsa rhythm and away we go.

Excellent intel Laitch. I just picked one up at the neighborhood true value (same price) to replace the fuel filter. Happy to report the driveway is not on fire.

[John Lang]

I disconnect the fuel line from the forward end of the fuel rail, stick it in a jug, then short the right side of fuse 4 to the left side of fuse 6. The pump does all the work.