'84 FJ Non Calif emissions gas tank, where is the vent?

[Pat Conlon]

I noticed today, I was draining my fuel tank with the cap closed (petcock on prime) and I was hearing the tank struggling to get air, and gas was just trickling out the petcock. I took my key and opened the cap...and woosh, gas flowed normally.

I have a non Calif tank with my original Calif cap.

I took the cap apart looking to see if there was any internal flappers, like my '92 but no...it's a tight sealing cap (it appears)

There is a little nub on the tank to the left of the opening, is this the vent? (it was painted over when I had my tank repainted from my accident last year) This nub is under the gas cap but not part of the cap seal on the opening.

Again it's a non Calif emissions tank. My old original Calif emission tank had a vent hose under the tank which went to the charcoal canisters and intake manifold, etc...

On the non Calif fuel tank there is no vent under the tank like the Calif version. The tank has gotta draw air from somewhere....?

Thanks folks... Pat

[Dan Filetti]

Pat-

Just drill a hole or two in the top of the tank, problems solved. 

Dan

[Pat Conlon]

Yep, I thought about drilling a small hole at the nub, but I thought I would check first.

[aviationfred]

Pat,
Have you considered sending Randy an Email? He may have a suggestion/information that would help.

Fred

[SlowOldGuy]

The tank breathes through the cap lock mechanism. 

I once got caught in the rain and in the process the base pad on my tankbag got saturated with water.  It sealed the cap off, which quit breathing, and I ran the carbs out of fuel until I figured out the problem. 

It was very obvious when I lifted the tankbag and the shape of the cap was vacuum-formed into the tankbag base.  I stuffed a rag under the pad to allow the cap to get air and everything was fine. 

Try "washing out" the cap lock mechanism with WD-40 and see if that helps.

DavidR.

[Pat Conlon]

Ok, Thanks guys, I *think* my problem is that I have a non-vented calif emissions cap on a non vented tank.
I see the online microfiche where Yamaha lists 2 different part #s for the cailf vs. non calif gas cap.

I do know that something is wrong...the gas just trickled out of the petcock until I opened the cap.

[FeralJuggernaut]

Just wait for the summer time when the vapors escape and leave a lovely residue around the key slot...   Oh, nevermind, that only gets us that don't polish frequently!