Pressurized gas tank?

[yamihoe]

My gas tank has started holding pressure (enough to blow the cap out of my hand when I turn the key)

I blew out the rubber line with compressed air and took the cap off and apart....didnt see any debris anywhere.

Is the cap vented and needing to be replaced, or is there another vent somewhere that I overlooked?

Thanks guys/gals

 

[motojoe122]

There's a pretty good chance you have one of the hoses off the tank pinched, I think. Gently lift the tank and take a look, while at it, pull down the lines that exit at the swing arm pivot at the same time when you lower it.

 

[yamihoe]

Ill try that. :thumbup:
but both that hose and the coolant overflow are still within the square ring thing at the bottom....so maybe I have it twisted somewhere....

it has been doin it for a month or so now so I cant remember if it started after the last time I had the tank up or not...

 

[FinalImpact]

Check this out. . .

When you lift the tank, confirm the hoses are NOT kinked. IIRC the cap vents into a port to one of those tubes. One is for rain water/overfill around the fill spout, the other is the vent.

http://www.600riders.com/forum/how-tos/36794-fuel-tank-dont-kink-hoses-w-pics.html

 

[yamihoe]

yes one is for water and stuff and the other is the actual vent.....

I wont be able to pull the tank until tomorrow, (when i have time and less gas in the tank ) but I wouldnt think that a kink would be able to hold the kind of pressure that my tank is building....i would guess 15+psi

 

[Gelvatron]

On your bike or car? I know with cars that there is an EvAP system it pressurizes the tank to make sure their are no leaks,

 

[philosopheriam]

On your bike or car? I know with cars that there is an EvAP system it pressurizes the tank to make sure their are no leaks,

Not true - the EVAP system on an OBD II equipped vehicle typically has a fuel tank pressure sensor. This monitors the pressure inside the fuel tank and can determine if there is an EVAP leak, i.e. if the fuel tank pressure never seems to rise regardless of the opening/closing of the vent valve and purging of the vapor canister, there is a problem. The EVAP system never actualy "pressurizes" the system.

Sorry, not trying to be a dick, just an important distinction.

 

[Gelvatron]

Not true - the EVAP system on an OBD II equipped vehicle typically has a fuel tank pressure sensor. This monitors the pressure inside the fuel tank and can determine if there is an EVAP leak, i.e. if the fuel tank pressure never seems to rise regardless of the opening/closing of the vent valve and purging of the vapor canister, there is a problem. The EVAP system never actualy "pressurizes" the system.

Sorry, not trying to be a dick, just an important distinction.

I was giving the op something to think about not a lesson on EvAP systems equipped on. Ob2 vehicles when I start those seminars ill be sure to invite you all at 15 an hour

 

[yamihoe]

2 ASE certs, so I am aware of this lol :thumbup:

I just was not sure if the gascap was vented or if it was a different line....I dont remember ever seein a vent solenoid on a bike, so I doubt that.

 

[TownsendsFJR1300]

Her's a pic of the inside of the tank, one's the vent, ones the drain for any water that gets up under the cap..

 

[Marthy]

Not true - the EVAP system on an OBD II equipped vehicle typically has a fuel tank pressure sensor. This monitors the pressure inside the fuel tank and can determine if there is an EVAP leak, i.e. if the fuel tank pressure never seems to rise regardless of the opening/closing of the vent valve and purging of the vapor canister, there is a problem. The EVAP system never actualy "pressurizes" the system.

Sorry, not trying to be a dick, just an important distinction.

I second that! It happen on my cage this week. Alarm light came on and I plug in the reader to get the code. EVAP leak... the gas cap was loose a bit.

 

[iSteve]

Not true - The EVAP system never actualy "pressurizes" the system.

Sorry, not trying to be a dick, just an important distinction.

I once owned a Cherokee that had a pump that would pressurize the tank right after start up and when I think had close to a full tank. It would monitor how long it took for the pressure to get back to spec.

Now that I think about it could have been lowering the pressure.

 

[yamihoe]

pictured the right one is the water and the other is the vent from the cap...
that is from the bottom lookin from the position of the pump.
thanks townsends!

 

[TownsendsFJR1300]

pictured the right one is the water and the other is the vent from the cap...
that is from the bottom lookin from the position of the pump.
thanks townsends!

Your welcome..

You may try blowing from the top down and paying attention to if one line takes more pressure than the other...

To elaborate on Randys (FinalImpact) post re the cap itself, ***Looking closely at mine, where the RED SEAL is under the cap on the tank itself, there IS an adjacent hole (very small but dead center of the RED seal on the tanK) in the ACTUAL FUEL CAP so the cap appears to be in the venting system.***

Further investigation into the cap is likely necessary.

Please post what you come up with... And good luck.

Scott

 

[yamihoe]

took apart the cap and cleaned everything,,,, still holdin pressure. Haven't taken the tank up yet....need to get around to it eventually.


http://img809.imageshack.us/img809/5680/42tqwayybsyqomvwnaqvtf.mp4

^^vid of what its doing exactly.

 

[TownsendsFJR1300]

took apart the cap and cleaned everything,,,, still holdin pressure. Haven't taken the tank up yet....need to get around to it eventually.


http://img809.imageshack.us/img809/5680/42tqwayybsyqomvwnaqvtf.mp4

^^vid of what its doing exactly.

I can't get the video to play....

 

[yamihoe]

thats probably for the better.....it is TERRIBLE.

 

[TownsendsFJR1300]

Did you get it straightened out?

 

[oaks]

Did you get it straightened out?

I was curious what you found, as well. Looks dangerous from your video. (A few frames reposted in this GIF.)

Take a few minutes to tilt up the tank and clear those vent hoses. Wouldn't be surprised if it affected your fuel flow eventually.

 

[yamihoe]

thanks to Townsends kick in the a$$ I pulled the cap off and took it all apart and cleaned everything this afternoon.
The vent line is clear all the way thru and nothing looked any different from the last time I took it off.
if this didn't work I will for sure need a new cap.