Pressure built up in the gas tank

[jasonk]

Ok so I've put several thousand miles on the '05 FJR and my dad had the bike before me. No problems ever in the 45k history of the bike.

Saturday I filled the bike up and commenced to do about 150 miles before our small group stopped to refill and grab something to drink. The bike performed flawlessly (as per usual) and I had a little over 1/2 a tank and I decided to top it off. I removed my magnetic tank bag and put the key into the gas cap as per usual. What happened next was insane. As soon as I cracked that sucker open, a mix of liquid and vapor gas spewed all over creation, proabaly a 4ft radius. As soon as I could instinctively shut the hatch I did. Then I let it hiss slowly for about 10-20 seconds before no more pressure remained.

It was hot out but the bike ran without this problem in the heat of FLA for it's first 40k miles so that might have contributed, but there is most certainly an overarching issue at hand.

I decided while I was filling up that a headspace would be my friend so I stopped after adding only 1gal to the half full tank. About 1/2 hr later I stopped and there was a slight "pssst" when I opened the hatch but nothing like what I saw at the gas station. As the sun went down and things cooled off there was no further pressure build up....even after 150 mile highway jaun. temps went from mid80's (a guess) to high 40's over the course of the day.

I got home and went to bed. Yesterday I elevated the tank and checked the vent tubes (removed them from the barbs on the tank and blew air though them to enure they were no plugged. neither was. Fast forward 24 hours til now....and here we are!

Any ideas? FWIW I searched the site and didn;t find anything on this, I was kind of surprised.

TIA for any and all help!

 

[Ignacio]

Any ideas? FWIW I searched the site and didn;t find anything on this, I was kind of surprised.
TIA for any and all help!

Talked about before here and other places by searching on fuel geyser site:fjrforum.com and other similar terms at Google.

I also think there may be an element involved with the refinery system switching from winter fuel to summer fuel configurations when combined with a nice warm spring day.

 

[jasonk]

Any ideas? FWIW I searched the site and didn;t find anything on this, I was kind of surprised.
TIA for any and all help!

Talked about before here and other places by searching on fuel geyser site:fjrforum.com and other similar terms at Google.

I also think there may be an element involved with the refinery system switching from winter fuel to summer fuel configurations when combined with a nice warm spring day.

Right on...thanks. Fuel Geyser....yeah that's it alright!

i will disassemble the filler neck and report back.

 

[jasonk]

Iggy,

Thanks for the quick help

so I took the filler cap off and I saw this, hell if I know but it looked like really fine "sand" maybe?

I cleaned all that out and blew some air through the orange "seal" for the vent tube. I could feel air going though the tube down under the bike. Hopefully that fixes it.

I also made the mistake of disassembling the fuel cap. I had good inentions as all of the "sand" had me wondering if all was right with the intenals of the cap. BEWARE there are several small parts bearing, springs etc that will attempt to fly across your garage if you aren't real careful. I feel kind of lucky I actually got the thing together.

 

[escapefjrtist]

Inquiring minds need to know... I can't imagine how that much debris gets in the filler area. Is the bike parked outside in the dirt and weather or in the middle of the Sahara desert? :blink:

--G

 

[jasonk]

Inquiring minds need to know... I can't imagine how that much debris gets in the filler area. Is the bike parked outside in the dirt and weather or in the middle of the Sahara desert? :blink:
--G

I wish I knew. It's crazy. The bike had about 40k on it operating out of Florida but I'd say a good 1/2 of that was outside FLA. The bike was also towed behind an RV around the US. I do know my dad never cleaned it out or even removed the filler cap. The biek was stored inside a clean hangar.

I'm thinking I run a couple tanks of gas through it and then change the fuel filter out. I know some of that stuff had to have worked it's way down the drain to get into the filter. Gotta go do some searchin on the fuel filter.

 

[03HiYoSilver]

Jason,

That is amazing. Run some SeaFoam in the system so it will clean out any other possible varishes, etc in your system.

https://www.fjrforum.com/forum/lofiversion/....php/t4754.html

Hopefully you won't have any more complications.

 

[SkooterG]

Gotta go do some searchin on the fuel filter.

Best of luck........there ain't no fuel filter. At least not one that you can do anything with.

Your problem with the dirt is the rubber vent and/or overflow hose that is coming out the bottom of your FJR. If the end 'slice' is facing the wrong way, dirt is blown up those hoses resulting in your mess. This was a fairly common occurrence in 2003-2005. The solution, that I and many have done, is cut the end of those hoses so that the 'sliced' end has the opening facing rearward.

 

[madmike2]

Gotta go do some searchin on the fuel filter.

Best of luck........there ain't no fuel filter. At least not one that you can do anything with.

Yup! Skooter speaketh deep truth.

Your problem with the dirt is the rubber vent and/or overflow hose that is coming out the bottom of your FJR. If the end 'slice' is facing the wrong way, dirt is blown up those hoses resulting in your mess. This was a fairly common occurrence in 2003-2005. The solution, that I and many have done, is cut the end of those hoses so that the 'sliced' end has the opening facing rearward.

Yup X 2!

 

[Constant Mesh]

The overflow outlet appears completely covered with sand. It is at the 10 o'clock position and the vent is at the 6 o'clock position.

 

[jasonk]

The overflow outlet appears completely covered with sand. It is at the 10 o'clock position and the vent is at the 6 o'clock position.

yeah i just took those pics to show how dirty it got. It's all clean now. I know some of that sand had to have gotten down into the the tank through the overflow drain though. Not much but there has to be some.

 

[jasonk]

Gotta go do some searchin on the fuel filter.

Best of luck........there ain't no fuel filter. At least not one that you can do anything with.

Your problem with the dirt is the rubber vent and/or overflow hose that is coming out the bottom of your FJR. If the end 'slice' is facing the wrong way, dirt is blown up those hoses resulting in your mess. This was a fairly common occurrence in 2003-2005. The solution, that I and many have done, is cut the end of those hoses so that the 'sliced' end has the opening facing rearward.

thanks, i had not gotten around to the search yet so you saved me some futile efforts about the fuel filter. I already saw the tip about trimming the hoses in another thread so that's been done. I guess I just ride then!

Thanks again for the info :biggrinsmiley:

 

[Fred W]

It is my opinion that the non-relief of pressure has more to do with the pressure relief mechanism inside of the fuel cap than it does with plugged fuel hoses. The cap has a combination check valve/ pressure relief mechanism that allows free venting one direction (into the tank) to displace consumed fuel, but will only vent out from the tank after some pre-determined pressure. The only reason for the pressure venting is to limit the evaporative emissions.

You say that you disassembled your cap. I wish that you had taken some pictures of the condition inside there. I've been meaning to do the same thing on mine and maybe eliminate the pressure function from the vent altogether.

And yeah, obviously if the hose actually is/was plugged it wouldn't vent, but that is a pretty large vent hose.

PS - I'm betting that it was hauling the bike behind an RV that was the reason for all the dust you found.

 

[TheAxeman]

You all just reminded me that vent hose is still in my tank bag after falling off on our covered bridges ride. Do I really need to put that thing back on? Maybe thats the reason I have been smelling raw fuel lately.

 

[jasonk]

It is my opinion that the non-relief of pressure has more to do with the pressure relief mechanism inside of the fuel cap than it does with plugged fuel hoses. The cap has a combination check valve/ pressure relief mechanism that allows free venting one direction (into the tank) to displace consumed fuel, but will only vent out from the tank after some pre-determined pressure. The only reason for the pressure venting is to limit the evaporative emissions.
You say that you disassembled your cap. I wish that you had taken some pictures of the condition inside there. I've been meaning to do the same thing on mine and maybe eliminate the pressure function from the vent altogether.

And yeah, obviously if the hose actually is/was plugged it wouldn't vent, but that is a pretty large vent hose.

I suppose you could be right but the fuel cap looked mint, not a bit of dirt or mis-positioned seals in there. I would suggest that if you are going to disassemble that cap that you do so very carefully and have a cloth down to lay the parts. There is a spring there that I think is made of pubic hairs. It's that small and it's curly so I assume it's not constructed of regular hairs. it helps position another pin that allows the key to be removed from the fuel hatch lock. There's also a "bearing" that I think is there to be kind f a check valve. Bottom line is that mine looked great but it took me a while to get it back together and functioning properly. For all that stuff that was under the black rubber seal (the circular one) I was surprised that none of it had made it into the hinged part of the cap assembly/locking mechanism.

I think that the small nipple was plugged.

 

[Fred W]

jason,

FYI, in case you didn't catch it, your post prompted me to dig into the cap. I think I figured some things out that may apply to you situation too.

Posted my experience here

 

[road runner]

How did I miss this venting issue ?

Very nice detective work and write up Fred :clapping:

Now I have more work to do. :angry:

 

[lnewlf]

Fred's deballing technique is da shizzzle-took about 3 minutes. Afterward I tried to cause an overflow problem by filling the tank to the top but no gas came out the vent hose..[unlike my FJ1200 which pees like a little girl whenever it's anywhere near full]

 

[Fred W]

Glad this is working for folks.

The true test will be what happens in 90+ degree summer when your tank is down near empty and you go to refuel. So far every time I've opened my tank I don't sense any sort of built up pressure or vacuum (as expected).