V-11 gas tank overflow leak

[Guest Brad M]

When my '04 Coppa Italia sits in the garage for a day or so gas drips from the overflow tube,which exits under the engine.

If I open the gas cap and leave it cracked, the flow stops. Any ideas?

[nose2wind]

When my '04 Coppa Italia sits in the garage for a day or so gas drips from the overflow tube,which exits under the engine.

If I open the gas cap and leave it cracked, the flow stops. Any ideas?

 

If the Garage is heating up, could be a little pressure build up in the tank (full)? and making it's way to the overflow. This would only occur if the vent side is blocked. Easy enough to check. Doesn't quite add up. I would start with the tank vent.

 

Good luck

[JoeV11]

Go on- how does one clear this vent? Mine does it in the parking lot at work, and thecompany fire department called me out to the bike the other day. I guess I need to fix it now. JOe

[pasotibbs]

Go on- how does one clear this vent? Mine does it in the parking lot at work, and thecompany fire department called me out to the bike the other day. I guess I need to fix it now. JOe

There are 2 drains under the filler cap the L/H/S is rain/spilt fuel drain from the cap assembly the R/H/S is the tank vent. The cap is held on by 4 ? bolts one under the cap and the others are the external cap bolts(12 o-clock 5 o-clock and 7 o-clock if I remember correctly)

[GuzziMoto]

The tank vent may have a one way valve in it to only allow air in to the tank to replace the space the fuel, that is used up as the engine runs, occupied. Sometimes this vent is installed backwards. But in your case, if it is there, it may not be letting pressure escape as it builds up in the tanl(due to fuel evaporating and/or temp increasing). The pressure build up may force fuel out the other line. Not really sure why or how. All I know is on my Griso it did the same thing and removing the one way valve stopped it. If you have this valve in the vent line, try removing it.