gas cap leaking gas.

[jagcofj]

Man it's seem I have another bug to work out. I was out riding yesterday stop off to eat when got back to the bike, gas was leaking from the gas cap it looks like it was coming out of the key hole.
My bike year is 1989. I never had this happen before on any of my other bikes I had in the pass.  Do you guy's think I should replace with a new 1.   

[FJmonkey]

This has been reported before. Normally right after filling up and just before a rest/meal break. Fuel is stored and pumped from tanks in the ground. This naturally keeps the fuel cooler than the ambient temperature. Now pump it into a steel tank sitting directly above a hot 4 cylinder air cooled engine that was just shut down. The fuel will expand as it heats up as all materials do. This is more noticeable when the fuel is filled to the top with the bike on the center stand and then parked shortly after on the side stand. I stopped filling the tank on the center stand because of this and have not had any issues since on my '86 or '89.

[jagcofj]

thanks for the info, I always full up the tank on the kick stand.  I did stop off and full the tank went about 5 miles to eat gas was coming out of the key hole..  I never had this happen before on bikes in the pass. 
Is this a normal thing. The bike pass inspection yesterday morning me happy about that.

[FJmonkey]

thanks for the info, I always full up the tank on the kick stand.  I did stop off and full the tank went about 5 miles to eat gas was coming out of the key hole..  I never had this happen before on bikes in the pass. 
Is this a normal thing. The bike pass inspection yesterday morning me happy about that.

This does happen on our FJs. Something to be really careful about if you use a magnetic tank bag. it can trap the fuel and peel off the paint on the tank around the cap. Unless you are trying to get that last 1/4 mile out of your tank then stop just before full like I do. I still get 200 miles on a tank (4 hours seat time) and that is plenty long before I need to take a break.

Make sure your over fill drain is not plugged. Open your fill cap and look for the drain hole near the hinge. Use compressed air and make sure you can blow air through it. This hole runs to the rear of the tank under the seat. Ever wonder what that tube is when you take your tank off? That allows fuel to spill to the ground and not on your bike under the seat near the battery next to a hot engine.

[racerrad8]

If the fuel tank vents are not venting the pressure must escape somewhere...

The tank drain at the rear is to drain off the overflow/spillage when filling, but coming out of the key hole means the tank is not venting.

Randy - RPM

[a.graham52]

If the fuel tank vents are not venting the pressure must escape somewhere...

The tank drain at the rear is to drain off the overflow/spillage when filling, but coming out of the key hole means the tank is not venting.

Randy - RPM

Wrong randy. The tank is ventin just fine.just not where it's supposed to

[Tuneforkfreak]

I would ask you this, if and when you shut off the bike ( engine hot thus heating the tank above) do you hear the cap venting? It sounds like a low frequency light sounding whistle. I had this same exact  issue and when I removed the cap and took it all apart I found that corrosion had set in on all the moving parts,kind of like a light white looking bunch of crud. I cleaned it all then lubricated all the springs and pieces then put it back together. Before I reinstalled it I worked the cap mechanism in and out with my hands until all the springs felt smooth ( it did not at first until I did it several times).  After I got it working smoothly and reinstalled, I could hear my tank venting when I shut off the bike. Ive not seen fuel come out of the key hole since Ive did this cleaning. Also I'll add that my drain port has always been clear. Not 100% sure but I think the pressure in the tank is meant to over ride the pressure of the springs tension on the cap seal, just enough to allow the gasses to escape (this is the whistle sound) then when balance is reached the seal resets itself. If the springs are nasty and corroded this valve action is interrupted and the gas tank gets out of balance, thus pressuring the tank giving the gas no where to escape but straight up through the key hole.

[jagcofj]

Thanks guy's for your help - yes the bike makes this sound out the gas cap when sitting still funny i just thought it was saying hello.

So do everything in the pics look good to you guy's. Man out of all the bikes i had this never happen. Over flow gas drains out the tub. 

[Tuneforkfreak]

Oh I see now, I've heard those guys talk about white and orange colored parts in their gas caps but when I took mine apart its completely different than the one you have.  I didn't understand what they where talking about when I finally took mine apart. Everything I said in my last post probably don't pertain to your cap, Sorry I didnt know there where different styled caps, I assumed those guys where just sniffing fumes and just saw orange and white things but I didn't want to say anything cause it sounded like they where having a good time. 

[Tuneforkfreak]

I should have thought of this, maybe those parts where removed from my cap long ago which is why I had no idea what they where talking about.  Hope I don't need them too bad cause I ain't got em.

[jagcofj]

I should have thought of this, maybe those parts where removed from my cap long ago which is why I had no idea what they where talking about.  Hope I don't need them too bad cause I ain't got em.

It's all good thanks though for trying. 

[FJmonkey]

I should have thought of this, maybe those parts where removed from my cap long ago which is why I had no idea what they where talking about.  Hope I don't need them too bad cause I ain't got em.

It's all good thanks though for trying. 

I took mine out as well a few years ago, now I have a slight gas odor in the garage, not all bad, the wife hates the smell so my Man Cave is safer.... 

[jagcofj]

I should have thought of this, maybe those parts where removed from my cap long ago which is why I had no idea what they where talking about.   Hope I don't need them too bad cause I ain't got em.

It's all good thanks though for trying.  

I took mine out as well a few years ago, now I have a slight gas odor in the garage, not all bad, the wife hates the smell so my Man Cave is safer....  

fjmonkey , i try to keep my wifie out the garage so she can't see anything new i may have bought.  I bought a set foot peg brackets off ebay and powder painted them in the house oven.
Man what a nut i can be, Don't ever use house a oven  to powder paint anything freaken paint drop off down in the oven. Now how have buy another 1. My wife will not no going to take her out to eat when she get in.
Will buy a new stove tomorrow.  

[FJmonkey]

fjmonkey , i try to keep my wifie out the garage so she can't see anything new i may have bought.  I bought a set foot peg brackets off ebay and powder painted them in the house oven.
Man what a nut i can be, Don't ever use house a oven  to powder paint anything freaken paint drop off down in the oven. Now how have buy another 1. My wife will not no going to take her out to eat when she get in.
Will buy a new stove tomorrow.  

I have always recommended to anyone that wants to cure paint at home to go find a cheap used oven at a garage/yard sale. If you don't have space to keep it, sell it when the job is done...

[jagcofj]

Wifie has a new stove. I went on ebay and order a new gas cap just to be safe. thanks for your help jf riders.