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2004 r1150RS fuel tank water drain

MOONDOG59

Active member
There is a hole in tank under filler cap. Is
this water drain or fuel expansion drain?
I am making sure the water drain isn't
clogged
 
fuel overflow
For when you slop more fuel in than will actually fit.
There's actually enough head space in the tank that it shouldn't expand that far (I guess it could though).

The seal is above that, so unless you leave it out in the rain with the gas cap open...

attached to that hole, inside the tank, is a hose, that leads through the tank to another fitting in the tunnel.
Another such hose terminates inside the tank (near the cap) to allow air to get in.

Within the tunnel there are two more hoses which lead to wherever the air is supposed to come from and where the rejected fuel is supposed to go.

A previous owner removed my carbon canister so for me they both point at the ground. I'm not 100% sure where they are supposed to go but I sure wouldn't worry about them if you're not having fuel-related problems.
 
fuel overflow
For when you slop more fuel in than will actually fit.
There's actually enough head space in the tank that it shouldn't expand that far (I guess it could though).

The seal is above that, so unless you leave it out in the rain with the gas cap open...

attached to that hole, inside the tank, is a hose, that leads through the tank to another fitting in the tunnel.
Another such hose terminates inside the tank (near the cap) to allow air to get in.

Within the tunnel there are two more hoses which lead to wherever the air is supposed to come from and where the rejected fuel is supposed to go.

A previous owner removed my carbon canister so for me they both point at the ground. I'm not 100% sure where they are supposed to go but I sure wouldn't worry about them if you're not having fuel-related problems.

No problems. Just bought bike yesterday so checking it out and making sure nothing is messed up and learning the bike. My other bike is a K1100RS so time to get use to new bike.
 
Keep the drain hole clean and rust free

The hole also allows water to drain from around the fuel filler area, it could be rain water or from washing your bike. I found that the metal tube runs down vertically a couple of inches and then it turns horizontally which causes water to collect and rust to form. I have a compressor with a blow gun attachment that I use to periodically blow out this tube and any water that collects in it. Then I spray some WD40 in the tube and blow it through.

If rust forms and clogs the tube you can buy green 22 gauge florist wire at a craft store and clean out the tube. It is a bit tough to turn the corner inside the tank but it can be done. Double up the end of the wire by about 1/4 inch and gently fish the wire down into the tube. It will become more difficult as you turn the corner. Doubling the end of the wire creates a smooth end and helps to get the wire into the tank. You wouldn't want to push the end of the wire through the rusted elbow and into the tank!
 
The hole also allows water to drain from around the fuel filler area, it could be rain water or from washing your bike. I found that the metal tube runs down vertically a couple of inches and then it turns horizontally which causes water to collect and rust to form. I have a compressor with a blow gun attachment that I use to periodically blow out this tube and any water that collects in it. Then I spray some WD40 in the tube and blow it through.

If rust forms and clogs the tube you can buy green 22 gauge florist wire at a craft store and clean out the tube. It is a bit tough to turn the corner inside the tank but it can be done. Double up the end of the wire by about 1/4 inch and gently fish the wire down into the tube. It will become more difficult as you turn the corner. Doubling the end of the wire creates a smooth end and helps to get the wire into the tank. You wouldn't want to push the end of the wire through the rusted elbow and into the tank!

This site is always a wealth of knowledge! Thanks
 
And eventually the tube ends and it is connected to a rubber hose that goes through the tank of gas and attaches at the fuel pump/filter plate. So be very careful poking wires down that hole.
 
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