ST1100 draining gas tank

I'm trying to figure out the fastest/easiest way to drain the fuel from the gas tank prior to removal.

Background:
'93 started puking green blood from the back of the engine (well okay it does look like it is from the V below the carbs).
There are 2 elbows that sometimes have loose hoses and sometimes those elbows have cracks; but, in either case, draining and removing the gas tank makes it easier to diagnose and/or dig down through the carbs to swap out parts/hoses or just tighten.

I have read that you can supply power to one of the connectors (12v) on top of the tank and don't remember which one to connect: there are white, black and clear connectors...

Can anyone tell me which connector needs 12 volts to get the fuel pump to spew gas?

Thanks,
Mark

I can't help with which connectors to use but couldn't you just siphon it?

It is quite a deep double tank... and the fuel pick up has to come from somewhere *really* near the bottom...
Yeah... I could; but, why?

Mark, I searched for a wiring diagram but didn't turn one up. Perhaps someone else knows where there is one.

In absence of a wiring diagram, you can diagnose which wires from the tank do what with a volt-meter. With the key on and run switch off, find which terminal is +12V (for the fuel level IIRC). Then flip the run switch (and as the pump runs) you should find the wire that is powered with the pump.

HTH.

Thanks John...

That does help.

Mark

Mark, it's the one furthest to the left on the tank when facing forward.
The green one is the earth and the one next to it is the low fuel sensor for the warning light.

Disconnect the hose off the outlet pipe and connect a tube from there into a container then connect the left most connector of the three on the top of the tank to a +ve supply and your pump will kick into action and empty your tank.

Mark, maybe you don't need to bother with all that. I always drain my tanks with a copper tubing in the tank, connected to a flexible hose (fuel line type) that is long enough to run to the container. I then start up a siphoning with a turkey baster. Once that siphon gets moving, it's only a matter of minutes before the tanks are empty. Make sure you put the bike on the sidestand to move the residual over to a corner (and make sure the copper tube is seated in that corner.)

Edit - You wouldn't need to bother with sidestand if you merely want to empty the tank far enough to remove it easy.

It's the left one with the white connector Mark.
Stick a + on there with a sharpie for next time when you forget.

I removed my tank with 3/4 full. Don't see why you must empty it. However be sure to unhook the fuel gauge connection on the left side or you will be soldering new wires

Ralph Sims

connect a hose to the line at the fuel filter then run it to a 5 gal gas can. Make sure less all the fuel fits.

turn the key on and it'll pump it out in short order

BuddingGeezer said:

I removed my tank with 3/4 full. Don't see why you must empty it.

Click to expand...

6 lbs/gal @ 3/4 * 7 = 31.5 extra pounds you have to lift out without the benefit of bending the knees. My back wouldn't like that too much.

Thanks all, done.

It took longer to find my wire and crimp tools and make a little 12v jumper than to do anything else.

Now that I've taken it out and emptied it I know that Mark and Paul were right... a siphon would work fine.
So next time I'll use a copper down tube connected to some siphon hose.

Mark

P.S.
It had over a half tank and my 5 gallon gas can handled it just fine.
I have always used an old rhyme for fluid weight "A pint's a pound the world around".
7 gallons would be ~56lbs.
In this case just under 30 lbs if the tank weighed nothing...

I've had my carbs on and off several times without removing the tank. Not necessary to go to that trouble.

Bill

It's the white connector, Mark. Brown/red wire (w/silver spots on mine). Pumping it out is easier than syphoning, IMHO. Put your jumper on the pump's spade for the white connector first, then the other end to the battery pos+ post to start pumping.



Clamp the output hose and pull it off the pump. Run some tubing to a container.



HTH

Regards, John

John.

What era is that gasoline jug from?

Thanks all.

My setup looked suspiciously like John's (except my gas can was a plastic 5 gal one without any patina of rust! ).

I'm now hunting for a radiator cap that I'll drill for a tire valve so I can pressurize and see what is leaking.
I'm still hoping that one of the clamps is loose; but, after inspecting with a bright trouble light it isn't looking like it will be the 'easy fix'.

Mark

Mark, try another way of it pressuring the system.

Drain the coolant out of your overflow tank.
Remove the small hose from this tank and keep it raised (it will still be attached to the thermostat housing end)
Attach a foot pump (via an airbed adapter or similar) into the end of this hose (make sure the footpump has a guage on it)
Use the pump to pressure the system at first to around 8psi then up to around 16psi and you should be able to look around for the leaks.

Floo,

That is a capital idea!

Thanks!
Mark
P.S.
Though I would have thought you'd say "and Bob's your uncle" to finish your post...

Close Mark, very close ........... Bob (Robert) is my dad not my uncle.

Hope you find the leak and it's cheap to fix.

Keith

Mark said:

....I'm now hunting for a radiator cap that I'll drill for a tire valve so I can pressurize and see what is leaking.....

Click to expand...

Mark, just go to AutoZone and borrow their free tester (they'll credit your card after you return it), BTDT.
[edit 2: http://www.autozone.com/autozone/inourstores/lat/latLanding.jsp?bodyContent=heatingAndCooling]
Take your radiator filler cap with you so you get the right adapter to go with the coolant system pressure tester. Plug it into the filler cap hole, pump it up to 18 lbs pressure and wait for the green blood to appear... might take a while, be patient. Like I said, BTDT (it was the right bank elbow's hose).

edit:

I'm still hoping that one of the clamps is loose; but, after inspecting with a bright trouble light it isn't looking like it will be the 'easy fix'.

Click to expand...

The elbows' hose clamps can be tightened without removing the carbs, BTDTx3, with the fuel tank out, a good light, and a 6mm midget wrench on an extension. I'm pretty sure I've poSTed about this technique, w/pics, here and on ST-Riders.net.

HTH

Regards, John