Tank Whistle (nothing in files section)

[David Allaband]

Hi everyone. My tank whistles out of the gas cap when the bike gets hot. When I open the tank there's a sound of suction. I assume the fuel is heating up and changing the air pressure in the tank and some kind of valve is blocked/broken.

I searched through the archives and found many people talking about the problem but no one explaining how to fix it. A few people said there are repair explanations in the "files" section but I can't find anything there.

Any help would be great!

No, I don't want to think of it as my bike singing to me. The wind sings to me, not the fuel tank. The fuel tank cries in pain.

Thanks!

[Mike 86 in San Dimas]

http://www.fjowners.com/index.php?topic=2024.0

might help some. in files titled gas cap info

Mike

[David Allaband]

Thanks Mike, I just found that. It's a great photo explanation of what's inside my cap, but it doesn't tell me what I'm looking for or why it might whistle. Now I know how to take it apart... what am I looking for?

http://www.fjowners.com/index.php?topic=2024.0

[Travis398]

You're looking for the post with the frogs in it, Heck if I know how to find it though

[Mike 86 in San Dimas]

It is whistling because it is venting, is whistling normal, maybe not when new. I am aware of many with this model year, that just tolerate it. I probably wouldn't. I my case (an 86) it would not vent and bike would stall out at extended freeway ride. Seventh picture shows white plastic goody removed. Try removing that. I did. Everything OK since.
I think they over complicated the cap making it automatically vent as needed instead of just having a constantly open vent hole.
Mike

[markmartin]

I removed the orange rubber flapper that fits inside the white plastic piece.  The whistling stopped.

[rktmanfj]

You're looking for the post with the frogs in it, Heck if I know how to find it though

http://www.fjowners.com/index.php?topic=3791.0

[ribbert]

I stuffed a rag in the filler hole with the cap open and gave it a blast of compressed air into the vent at the lower left of the tank.  A lot of crap came out (hence the rag in the opening) and it's never whislted since.

[Travis398]

You're looking for the post with the frogs in it, Heck if I know how to find it though

http://www.fjowners.com/index.php?topic=3791.0

ahh it's so easy even a newbie could find it.

isn't it funny how this thread is just like the other one, someone is having a problems with the gas cap whistling so they ask how to fix it.
Everyone refers the guy to a file that says absolutely nothing about fixing the whistling.

Then they wonder why the guy doesn't get it..........Probably because that file doesn't say shit about fixing it. Maybe someone should add a note in the file explaining what to remove if their gas cap is whistling.  Other than that the file is useless........any 5 year old with a screwdriver could figure out how to take the gas cap apart. It's not rocket science.

[soundmindryan]

You're looking for the post with the frogs in it, Heck if I know how to find it though

http://www.fjowners.com/index.php?topic=3791.0

ahh it's so easy even a newbie could find it.

isn't it funny how this thread is just like the other one, someone is having a problems with the gas cap whistling so they ask how to fix it.
Everyone refers the guy to a file that says absolutely nothing about fixing the whistling.

Then they wonder why the guy doesn't get it..........Probably because that file doesn't say shit about fixing it. Maybe someone should add a note in the file explaining what to remove if their gas cap is whistling.  Other than that the file is useless........any 5 year old with a screwdriver could figure out how to take the gas cap apart. It's not rocket science.

I experienced the WOT/high speed fuel starvation AND the tank whistling. Performed the flapectomy and that cured both the whistling and the fuel starvation...BUT... Now, after returning home after riding on a HOT day, and parking in the shade of my garage, the heat from the engine soaks the tank and expels higher amounts of fumes into the garage than I had previously noticed before the flapectomy. Much higher and stinkier. So... It's a tradeoff but I can see why the mfr added the flap. Th fumes expelled with an open vent are not acceptable for a closed showroom or other enclosed area.

[FJmonkey]

Other than that the file is useless........any 5 year old with a screwdriver could figure out how to take the gas cap apart. It's not rocket science.

Not rocket science but wait till that 5 year old looses the microscopic ball-bearing that shoots out during dis-assembly, never to be found again.

[Travis398]

Other than that the file is useless........any 5 year old with a screwdriver could figure out how to take the gas cap apart. It's not rocket science.

Not rocket science but wait till that 5 year old looses the microscopic ball-bearing that shoots out during dis-assembly, never to be found again.

You don't have to be 5 to loose that ball, I'm sure a few adults have already done that.........and again, that useless file everyone refers to doesn't even mention the ball is going to "shoot out during dis-assembly"  or when it is going to shoot out.

[RichBaker]

It is whistling because it is venting, is whistling normal, maybe not when new. I am aware of many with this model year, that just tolerate it. I probably wouldn't. I my case (an 86) it would not vent and bike would stall out at extended freeway ride. Seventh picture shows white plastic goody removed. Try removing that. I did. Everything OK since.
I think they over complicated the cap making it automatically vent as needed instead of just having a constantly open vent hole.
Mike

They all whistle, even new....  Many a time I've been standing in the showroom of my LBS, listening to the concert.  Unless your bike has the dreaded clogged vent, which causes the dreaded "tank vacuum, no fuel flow on the interstate" engine quits, a flapectomy is a waste of time...
Even then, usually just a simple cleaning of the vent passages will fix the problem.

[FJmonkey]

They all whistle, even new....  Many a time I've been standing in the showroom of my LBS, listening to the concert.  Unless your bike has the dreaded clogged vent, which causes the dreaded "tank vacuum, no fuel flow on the interstate" engine quits, a flapectomy is a waste of time...
Even then, usually just a simple cleaning of the vent passages will fix the problem.

I will chime in here, I hesitated in doing the flapectomey as a new owner many years ago but did take the cap apart and clean things up a bit. Have not had the fuel cut out since then. The cap still sings like a pinched venting balloon. As long as it vents all is working.

[FJ Flyer]

Its an FJ...it sings.  Part of its personality.