Gas tank venting

[Peckerwood]

Going on a run tomorrow and all of a sudden my gas tank won't vent. The vented cap is working perfectly. Leaving early tomorrow. Any quick ideas or fixes, or will I be unscrewing the gas cap every 5 minutes on the ride?

 

[chubs]

Going on a run tomorrow and all of a sudden my gas tank won't vent. The vented cap is working perfectly. Leaving early tomorrow. Any quick ideas or fixes, or will I be unscrewing the gas cap every 5 minutes on the ride?

Sounds like that cap vent isn't venting! could there be something restricting the fuel flow intermitantly?

 

[Sven]

As soon as you top off the gas... Bawwwwwwwwwww... and you pull over within yards of travel. I'd waste a cooking pot, drop the cap in some vinegar, boil the cap. Probably better out on the bbq side burner. You'll choke on the vapor. Then rinse in water, then brake clean the holes, then top off the gas and if you keep on going?

Signed,
NOLTT

 

[Sven]

Or... where is the petcock in all this? We have flow with cap off or on to tell if it's the cap? Top the tank off to tell. If you're saying the cap is good, then the dribble goes like this... cap's vent/petcock flow/kinked-swollen fuel line/sticking float.

 

[FrankBDPS]

When mine was starving for fuel a piece of the tank liner had gotten sucked down over the outlet in the tank. Does an 04 still have the dual tanks?

 

[Peckerwood]

Here's the details (and by the way, thanks for the replies). Took a short ride thursday, parked the bike in the garage. Went back out to the garage a few hours later and smelled gas vapors. Having been through this before, I suspected a venting problem, so I unscrewed the cap, and a little bit of pressure escaped. Went on another short bar run yesterday and the bike would crank but not catch, this after sitting in the sun for maybe a half hour. I unscrewed the cap and a LOT or pressure escaped, and the bike turned right over. Vent works because I can easily suck air through it. And I do have dual tanks.

 

[BWG56]

The vent is only a one way vent, to keep it from vapor locking, if the white thing is still on the cap. You have the opposite problem

 

[FrankBDPS]

Ker, he has an older bike that dosent have the white thing like you're single cap did. It has to be an issue with the right hand cap. You should be able to suck air from the outside but not blow back in. Or blow out from the inside but not suck back in. Take a good look it's simple. What caps are you using?

 

[Peckerwood]

Thanks BW. I removed the paint savers years ago, I'm running HD caps. I realize the vent is one way. Sucks in, can't blow out of it. Went to the HD dealer yesterday, my cap behaves exactly as a brand new out-of-the-box cap.

 

[BWG56]

Have you done anything to the bike recently?

 

[FrankBDPS]

I just checked my cap and it is the same way lets air in not out. So really there is now way of letting pressure out of the tank.

 

[BWG56]

You would think with pressure in the tank, it would push it out the carb overflow

 

[FrankBDPS]

I have never noticed pressure like that in my tanks.

 

[Peckerwood]

Serviced the air filter. Cleaned the crankcase vent filter.

 

[Peckerwood]

You would think with pressure in the tank, it would push it out the carb overflow

I'll look into that in a couple of minutes.

 

[Peckerwood]

So really there is now way of letting pressure out of the tank.

I've been wondering about this since the problem arose. Doesn't seem right, does it. Harley tech told me yesterday their split tank models have a vent hose coming from the tank. I removed my dash, there is a nipple on the right tank that looks like it could serve this purpose, but it is capped off by the factory, and always has been. WTF???

 

[FrankBDPS]

Mine does have a hose that runs from tank to tank. And also a nipple that is capped off. That hose allows the left tank to vent since the cap on the left is solid.

 

[FrankBDPS]

Here's a pic. The cross over hose is towards the top front and the unused nipple is on the right tank next to the controller.

 

[Peckerwood]

Mine does have a hose that runs from tank to tank.

Just checked that, it's not blocked. Also checked the carb overflow hose, it's clear. I'm starting to think the vent on the gas cap was partially blocked, and when I took it off to check it by sucking on the cap, I might have dislodged a piece of debris. Can't think of anything else to look at, so I guess I'll make the ride and see how it performs. Worst case is I have to keep unscrewing the cap on the ride to vent the tank. Thanks for all the suggestions. I have a couple of hours before I leave, if y'all have any more idears, let me know.

 

[BWG56]

Serviced the air filter. Cleaned the crankcase vent filter.

I wonder if cleaning it, did you move crud and block it up? can you move air thru it?