Fuel leak from vent tube.

[Chupacabra]

Hello everyone.
   I have a new problem and was wondering if someone may have some experience with the issue.
I started seeing a small drip of fuel from the vent line connected to the back of the tank on occasion. Rode around town Sunday morning and parked in the driveway, in the sun. I came out several hours later to find a nice puddle of gas and a constant drip of gas from the vent tube. The tank had pressure from sitting in the sun. First time this has happened and not sure why. Is there a pressure relief inside the cap? It is a basic 2000 model.

Any help will be appreciated

[sandy]

The only way I know this could happen is if the tank was overfilled. Ride it 10-20 miles and check again.

[The emperor has no clothes]

The only way I know this could happen is if the tank was overfilled. Ride it 10-20 miles and check again.

I don't know about that Sandy. I'm too impatient to overfill when I gas up, unless I know it's going to be a stretch till the next station. I filled up one time and then went to McDonalds for lunch. When I came out I had a nice wide open space of no cars parked around me. It was shooting out the vent hose like it was under 20 psi of air pressure. I wouldn't doubt there might have been half a gallon came out. Now this was at 110* in direct sunlight. I think if the rubber fill gasket is making a good seal and it's in direct sunlight it might do it with anywhere close to full.

[Jess from VA]

Yes, and here's the rules.

If you need to eat or shop or visit, always do those things before a fillup.  Never fill up and run a mile or two to park in the sun.   Or, leave it a half gallon short of full if you must.  

I always fill to the tippy top, sitting on the bike centered up (and on an interstate, that's about a half gallon more than you think it will take, as long as you have a pump that will feed slow), but I always depart and go miles before parking again.  It's 50 miles home from the closest non-corn gas I can get.

I don't know if black bikes are worse (for heating up under the sun) or not, but that's what I have.

I also don't know if once a full tank starts cooking out the vent in the sun, if it sets up a siphon effect.

Last, reset one trip meter at every fillup.  Get familiar with how many miles to a tank or to reserve (which is 1.1gal).  Short of 80mph hauls or headwinds, most bikes get pretty consistent mileage (my interstates are 220 to reserve).  This will give you a better idea of how much gas you have left, or how much you will need to fill up (less a half gallon, if necessary).  It's more accurate than looking down the hole (especially if you fill on the kickstand).

[Chupacabra]

I did fill it up before I parked it. I could also hear a hiss of pressure from the cap. Not sure what I did different this time compared to other fill up's and the temp outside was around 80 F. I know its sat in 100 deg plus with a full tank several times without any problems. Not sure what changed.

Thank you for your reply's. 

[The emperor has no clothes]

I did fill it up before I parked it. I could also hear a hiss of pressure from the cap. Not sure what I did different this time compared to other fill up's and the temp outside was around 80 F. I know its sat in 100 deg plus with a full tank several times without any problems. Not sure what changed.

Thank you for your reply's. 

From my perspective, it's a full tank and direct sunlight on it.