Slow fuel leak out breather hose

[Tahlen]

So the last few days I have noticed a slight bit of fuel on the ground under the bike and have traced it to one of the rubber hoses down by the kickstand - slightly wet to the touch, smells of fuel. This hose connects to the riders right side on the bottom of the gas tank - fuel breather according to the service manual.

After a little digging it appears the issue has been caused in the past by the metal tube that continues the breather line up to the top of the tank having a leak. This would obviously allow fuel to slowly drip into the line making it's way to the ground.

Good news is I just started blinking reserve. I plan to drain the tank and look at it tonight. In the thread I found, the guy mentioned fixing it with JB weld. Anyone know of any potential issues with JB weld and fuel reacting? Any other ideas for possible cause while I'm at it?

Will update when I know more.

 

[tejkowskit]

Jb weld claims to be completely resistant to gasoline. Should be fine to use to seal up the crack or small hole.

 

[kenh]

So the last few days I have noticed a slight bit of fuel on the ground under the bike and have traced it to one of the rubber hoses down by the kickstand - slightly wet to the touch, smells of fuel. This hose connects to the riders right side on the bottom of the gas tank - fuel breather according to the service manual.

After a little digging it appears the issue has been caused in the past by the metal tube that continues the breather line up to the top of the tank having a leak. This would obviously allow fuel to slowly drip into the line making it's way to the ground.

Good news is I just started blinking reserve. I plan to drain the tank and look at it tonight. In the thread I found, the guy mentioned fixing it with JB weld. Anyone know of any potential issues with JB weld and fuel reacting? Any other ideas for possible cause while I'm at it?

Will update when I know more.

What is the temperature range that you ate noticing this? If it is warm, say above 80 degrees F, then the fuel that you are smelling could be fuel vapors that have condensed back into liquid and are exiting through the tube.

 

[Tahlen]

It has been 85-90 Fahrenheit over the last 2 weeks or so. Did not notice the issue before then, didn't even think of connecting the two. Is it possible that heat can create enough vapor to make the line moist and spots on the ground under the bike? Why haven't I heard of this before? Blah

 

[FinalImpact]

It has been 85-90 Fahrenheit over the last 2 weeks or so. Did not notice the issue before then, didn't even think of connecting the two. Is it possible that heat can create enough vapor to make the line moist and spots on the ground under the bike? Why haven't I heard of this before? Blah

Mine does that when hot an full (>¾t). Maybe a dribble if she laughs too hard too! Getting older you know! Blah

 

[kenh]

It has been 85-90 Fahrenheit over the last 2 weeks or so. Did not notice the issue before then, didn't even think of connecting the two. Is it possible that heat can create enough vapor to make the line moist and spots on the ground under the bike? Why haven't I heard of this before? Blah

Mine does it at that temp range too. It is a combination of the dark tank color and the sun (heat). As soon as the tank is in the shade it stops.

 

[Tahlen]

Yep, was thinking it over more and if it were truly a leak then the control variable for puddle size would seem to be time - not the case. It sits for 16 hours in a shaded carport at home and 8 hours in the sun at work. Very small puddle at home from what I assume is when it cools down after I get home. Large puddle at work where it spends all day in the hot sun. :spank:

I filled it up again and I'll try parking in shade at work. Had me scared for a second but I think this one is simple.

 

[tejkowskit]

I'm gonna start looking for this! I've never noticed it and my bike frequently sits out in this temp range during the summer.

 

[TownsendsFJR1300]

Just an FYI,

Both the breather and over flow hose SHOULD come out on the RIGHT side of the bike (pretty much together, Page 2-40, 07 Yamaha manual). There's an actual "loop" the hoses go thru.

 

[Tahlen]

Just thought I would confirm that the combination of 90+ degree weather and direct sunlight was the cause. Topped the tank off yesterday and no leaks all day today with her sleeping under a tree.