Singing gas cap

[GaryL22]

Hello,
I noticed today that my gas cap on my 91' FJ is making a venting noise (a musical note actually). I'm not sure if it is venting in or out. I noticed it today after a short ride in the hot sun, I had about 1/4 tank. Is this a problem or a characteristic? Is there an easy fix without spending money? Gary

Also how do you read the Reserve switch? Does on mean you have switched the reserve on? Or does on mean the full tank position and the Res position switches the reserve on?  

[aviationfred]

A singing FJ is a happy FJ. You are correct. The note you are hearing is pressure being relieved from the fuel tank through a flapper valve in the fuel tank.

With the reserve switch at the on position (aft side down), you are on the main tank. With the switch in reserve (forward side down), you are on the reserve circuit and are able to run the tank dry. Also, in the reserve position the word reserve is printed on the trailing side of the switch.


Fred

[great white]

It's not a problem, just a characteristic. My 89 does the same thing after a run. Just kinda sitting there and lets out a "hooooo".

There is a "fix" somewhere on the board which involves (IIRC) removing the valve from the cap.

I left mine, I kind of like it. It's made for some funny moments when I park the bike, walk away and the bike goes "hooooo" while others around the bike start looking for where the sound came from......

[Country Joe]

I, too like a singing FJ. It's just another part of their charm.

[GaryL22]

Thanks for all the replies, I'm glad to hear it's common and I will leave it be. On the Res info I thought it was that way but I was not sure and it's too hot around here to run out. I saw the red low fuel light tonight for the first time too.

I've only ran my bike up to red line a few times and held it and I noticed afterward the bike seem to sputter for about 20 seconds. I was thinking it was starving for fuel caused by a faulty tank vent or fuel filter. To be safe I put on a new Yamaha brand fuel filter tonight. I test drove it after and I think it is running better but I'm not going to jail to find out.   Gary