Gas leaking from the fuel breather hose

[lukaledoux]

I just took my bike out of storage today, it has been sitting in a barn all winter. I winterized it properly in the fall, the tank was full of stabilized gas.

I went to flip the tank vertically to put the battery back in and a lot of gas started leaking out one of the overflow hoses on to the ground. According to the service manual, it's the fuel breather hose (driver's right, with a white marking on it).

It does not do this when the tank is in it's normal position, and the tank was still completely full so clearly nothing came out over the winter. There are also no signs of kinks in the hoses. My guess is something is ruptured along the roof of the tank and gas gets through when the tank is vertical

Anyone know what might be going on exactly or has had this problem before? I'd like to know more before I potentially have to empty the gas and remove the fuel pump to take a look.

 

[iSteve]

A breather is a hole at the top of your tank that lets the tank breath. You need to let air in as the fuel drops or air out when pressure builds up in the tank. It doesn't care if it is breathing air or fuel so when you tip your full tank up the fuel is going to come out. This is why the hose is under your bike.

 

[tejkowskit]

^ bingo :mikebike:

 

[lukaledoux]

This did not happen in the fall when I put the bike away. The tank was also full then and nothing came out. It feels silly that you should have to clamp the hose everytime you flip the tank up. I was under the impression that this alone should not cause fuel to discharge.

A breather is a hole at the top of your tank that lets the tank breath. You need to let air in as the fuel drops or air out when pressure builds up in the tank. It doesn't care if it is breathing air or fuel so when you tip your full tank up the fuel is going to come out. This is why the hose is under your bike.

 

[Motogiro]

As the temperatures rise the fuel can expand putting pressure against the fill cap washer. Lifting the tank with the gas pressurized can push the fuel past the washer. Inspect your washer and if no fuel is exiting with the tank down you're probably okay.

 

[TownsendsFJR1300]

Just to add to the above, besides the vent, there's also an over flow hose. Should you overfill, the fuel will run into this hose(just under the cap) and out the adjacent hose(lower right side of the bike).

The below pic's show the inside of the tank and the TWO lines, one vent, one over flow.

**When you flipped the tank back, fuel ran out and into that line, as it should, the fuel level would have been above the filler cap..

Your fine

Just make sure both those rubber hoses are NOT KINKED once the tank is back down (or you'll be posting again )

Bet you topped it off AFTER you pulled the battery...

 

[lukaledoux]

Well, it seems no one is alarmed except for me, so I guess I'll just roll with it and trust you guys!

I do swear that I filled it before, because I rode to the gas station with the bike. Either it didn't leak for whatever reason, or I'm slowly losing it! :cheer:

Thanks for the helpful pic Scott, I've also been following your Stebel Nautilus installation guide quite closely. I'm installing my own this weekend.. many thanks!

Just to add to the above, besides the vent, there's also an over flow hose. Should you overfill, the fuel will run into this hose(just under the cap) and out the adjacent hose(lower right side of the bike).

The below pic's show the inside of the tank and the TWO lines, one vent, one over flow.

**When you flipped the tank back, fuel ran out and into that line, as it should, the fuel level would have been above the filler cap..

Your fine

Just make sure both those rubber hoses are NOT KINKED once the tank is back down (or you'll be posting again )

Bet you topped it off AFTER you pulled the battery...

 

[TownsendsFJR1300]

Well, it seems no one is alarmed except for me, so I guess I'll just roll with it and trust you guys!

I do swear that I filled it before, because I rode to the gas station with the bike. Either it didn't leak for whatever reason, or I'm slowly losing it! :cheer:

Thanks for the helpful pic Scott, I've also been following your Stebel Nautilus installation guide quite closely. I'm installing my own this weekend.. many thanks!

Shoulda bet me then!!! (I'm the one loosing it!)

Your tank should be fine, it doesn't take much to come out the overflow or vent line... KUDO's on storing it properly BTW. :thumbup:

BTW, the biggest part for the horn install (and I just happened to luck out the first time) is to make sure its low enough to clear the inner black fairing. You have to, at some point, work backwards, ie, put the horn where it clears, then make the bracket follow around to that point. And use a self locking SS nut. You don't want any of that coming loose..

 

[FinalImpact]

The key difference is this: once lifted upright does it continue to poor out, or is it simply the line volume dripping and making a 6" circle?

Fuel being so thin it will flow and cover a pretty good area. i.e. an once of fuel could make 10" diameter of fuel on a flat non-absorbent surface.

I recall the first time I lifted the tank on my bike the previous *lifter* had kinked the hoses. Water smelling of fuel poured out. It was simply stuck in the lines either as condensation or overflow from the drain around the gas cap fill area.

Point; during the transition of upright to down (i.e. event of layover), it may leak some but should not continue to drain while down (in your case - tank lifted).

 

[lukaledoux]

As long as the tank was vertical, gas just kept pouring out. The tank was to the brim with fuel so it sounds like from what others are saying, that its normal since the tank cap will be submerged.

The key difference is this: once lifted upright does it continue to poor out, or is it simply the line volume dripping and making a 6" circle?

Fuel being so thin it will flow and cover a pretty good area. i.e. an once of fuel could make 10" diameter of fuel on a flat non-absorbent surface.

I recall the first time I lifted the tank on my bike the previous *lifter* had kinked the hoses. Water smelling of fuel poured out. It was simply stuck in the lines either as condensation or overflow from the drain around the gas cap fill area.

Point; during the transition of upright to down (i.e. event of layover), it may leak some but should not continue to drain while down (in your case - tank lifted).