Fuel tank breather hose leak

[binarystarr]

Hi all


Just noticed fuel is dripping from the fuel tank breather hose.


Any ideas as to what could be causing that?

[Falcon 269]

You sure it's the tank breather hose and not the carb overflows?

If the latter, suspect sticking float (fairly significant outflow, though), a leaky float needle (not common) or a leaky float needle seat O-ring (a lot more common).

http://www.yamahafz1oa.com/forum/showthread.php?t=103599&highlight=found+carb+failure+mode

[Phil TK]

If the latter, suspect sticking float (fairly significant outflow, though),

My FJ suffered from that until I got the carbs out and cleaned the bowls and float pivot -and replaced o rings and needle jets. However a temporary cure that often worked was to whack the errant carb bowl a few times with the end of a wooden hammer handle.

[locksmith]

I concur, a couple of sharp taps on the carb bowl can be effective.

[binarystarr]

Many thanks guys, haynes manual arrived today so will be out this weekend with the tool kit.


I suspect i may have possibly overfilled the tank but this is a good excuse to get my hands dirty and check a few things over.

[taksi]

My injected '08 FZ1 does it as well in the sun. No carbs to bash so any other ideas?
 
Taksi

[Falcon 269]

Just a wild guess ... too much fuel, expanding when it gets warm?

[binarystarr]

Falcon, i think thats more than likely the problem. Only thing is it didn't leak until several days after filling. I guess it may take a while for it to condense and make its way down the tube.


I'm not too worried. Will keep an eye on it and get greasy in the meantime.

[Falcon 269]

Leaking due to overfilling/expansion would normally be immediate to my mind.

Has it been raining on the bike recently?  I wonder if you've had water get around the tank cap and find it's way out via the overflow hose.