T350 fuel tank cap leak, ruined the paint
Posted: Wed Feb 26, 2014 9:54 pm
I have a strange problem with either the gas cap, or the rubber gasket on my T350. Not sure if any of the other caps for the T series are the same or if anyone has had this issue. The cap & gasket (which is a NOS genuine Suzuki part) seem to seal just fine - for example, even with a full tank, I can rock the bike back & forth, and no fuel at all gets out, and none comes out while riding. But when it's been parked a while, I come back, and fuel has somehow seeped out, dripped off the edge of the cap & you can see where it's been running down the outside of the tank. I'm thinking it's something to do with heating of the tank causing vapors to vent out the cap, but why does it drip on the outside? I can see the center of the cap has a hole with a drain, and then there are 2 small vent holes up near the top of the cap. The cap assembly seems to have been press-fit together. This has happened not only while on the sidestand, but on the centerstand, too (so the bike is perfectly level). I have even tried taking the cap off right after a ride, drain any fuel from the inside of the cap, then replace it, but later on at some point it's been dripping again. 
Below is a photo of the cap & gasket (I even bought another one to try, assuming that the first one was somehow defective, but same results...) Maybe a dumb question, but I don't have the gasket upside down, do I? I put it on in what seemed the natural direction (the way it sits in the photo below, but seated as far down as it will go, under the locking tangs).
And somehow, the seeping fuel got in underneath the clearcoat around the filler neck, and ruined my new paint job (see other photo below). I temporarily added a bead of clear epoxy around the filler neck to stop that, but now I've pulled the tank off for a re-paint. I just don't want this to happen again after I re-paint. Anybody had this issue? Any ideas or help would be really appreciated.
Below is a photo of the cap & gasket (I even bought another one to try, assuming that the first one was somehow defective, but same results...) Maybe a dumb question, but I don't have the gasket upside down, do I? I put it on in what seemed the natural direction (the way it sits in the photo below, but seated as far down as it will go, under the locking tangs).And somehow, the seeping fuel got in underneath the clearcoat around the filler neck, and ruined my new paint job (see other photo below). I temporarily added a bead of clear epoxy around the filler neck to stop that, but now I've pulled the tank off for a re-paint. I just don't want this to happen again after I re-paint. Anybody had this issue? Any ideas or help would be really appreciated.