My 09 Fatboy started this today
Gas comes out from under cap and also from vent line
my Dyna Never did this

 

Mine on a hot day after filling it up to much; it will mark it's spot thru the vent hose.
Coyote

 

I had this same thing happen to me but only once since owning my Xbones for nearly two years. The issue of my bike leaking from under the gas cap actually had to do with the fact that it was not tightening down all the way. I guess over time, the chrome outter cap looses some of its grip on the part that actually threads and seals. I had gas leak from under it twice until I realized by looking at the cap from a low angle that it was sitting kind of high. Now I just make sure to add some good downward pressure while I tighten it to make sure it seals all the way.

Not sure however, why I happened to have some gas come out from the vent line at the same time on the first of these two occasions. I filled my tank up same as usual. In fact I probably used to over fill it more when I first got my bike because as a new rider, I was not used to properly gassing up a motorcycle. Why it didn't leak or overflow in those earlier instances is beyond me!

Best I could ASSUME is that the fuel system on my bike needs to maintain some sort of consistant pressure to work right and this is partly regulated by proper gas cap seal and an open vent line (as is the case with my car's coolant system). As such, when I failed to tighten the gas cap properly (equal to a bad coolant cap on my car) that system pressure was thrown off and gas started to find its way out from what ever opening was available. I got this idea because my car's cooling system has a similar overflow line and it kept leaking out coolant. The problem ended up being a faulty coolant cap with stripped threads and after I replaced it with the new one the problem stoped. The idea seemed plausible to me and now I just make sure that my gas cap is on good and tight by inspecting it both visually and by feel. I may be completely wrong in my assesment and if so, please don't laugh at me too hard! But after those two back to back incidents, I have not had this problem happen again.

 

Happened to me today. 35 degrees C, filled her up to the brim. Leaking like a sieve

 

I NEVER had that happen on my bike.

 

100 degrees outside today in Virginia, filled the tank as I always do while out to lunch. Came out at 3:00PM to head home and started the bike. Started to smell gas and looked down to see fuel pouring out from behind the air filter, the vent by the back tire and the gas cap. Bike shut down. Moved the bike out of the parking spot and started it again, ran about 6 miles and stopped to see a friend. Came out to start it about 1/2 hour later and it did the same fuel pouring out. Got it started again and hit the highway and ran about 20 miles to my mechanic friend. Did not do it again after it set for 1/2 hour. Got home and let set for a couple of hours in the hot sun to reproduce the same thing, no can do.

I have run this bike hard and in all kind of weather, and never had this happen before. I understand the fuel expanding during hot weather, but never had this happen when it's hot.

Question is, do I have a problem or not?

 

For those of you with leaking caps. This is a pretty common problem and I've been through it. When you put your cap on until it clicks, push it down with the palm of your hand and turn it again. You'll get about another quarter turn out of it and it will seal. Rode Kaws for 30 years and their gas stayed in the tank where it belongs.

 

I have a 2003 XL883C and on sunny days pressure builds up in the gas tank. The fuel cap does not vent and my fuel valve is closed. If I don't relieve the pressure by loosening the fuel cap before opening my fuel valve, fuel will dump out the vent line situated on the right lower side of the bike. I'm assuming that the lack of a vent in the fuel cap is for safety reasons in case you tip your bike gas will not flow out and ignite. Also this problem occurs regardless of the fuel level in the tank.

If you close your fuel line when your done riding it does not seem to vent and pressure may build up on sunny days. Therefore, removing the pressure in the tank by loosening the gas cap is critical before opening your fuel valve in order to prevent fuel from leaking out.

 

Yep my 09fxstc did this for the 2nd time sence I've owned it, the 1st time I was at a stop light after filling up.wjen the light turned green I broke traction , I had thought that I had run in an oil spot from a car or truck. The 2nd time was yesterday after I filled up I rode over to a brothers house, parked in his drive way an we both noticed gas running on his driveway right in front of my back tire. At first I freaked out an he asked if I just filled up an I said yep. He showed me where the over flow hose was. So now I don't fill her to the brim. Lesson learned

 

I got custom two and a half gallon gas tanks like old shovel-heads had. The tanks are linked with a couple hoses. The gas cap on the right hand side is vented. The only hassle hits when running out of gas. I have to lean the bike over to the left and let the little gas still in the right hand side make it over to the left and the fuel petcock.