Fuel leaks when i open my gas cap

[EC-450f]

Hello all.  i have a weird concern.  When i open the gas cap on my 07 WR450 i get fuel running down my tank and on to my seat as if the tank is under some slight pressure.  Is this normal.  This is my first dirtbike so i have no idea about what is normal or not.  Thanks in advanced for your help.  

[William1]

There is a one way check valve. Air can get in but not out. If your tank is full, the bike then in the sun, it will pressurize. Also may pressurize during slow riding due to engine heat.
Hold the bike vertical, slightly loosen the cap to let the pressure escape.

[FORMA MOTO]

Remove the aftermarket breather tube and install regular fuel line hose

[EC-450f]

42 minutes ago, THE KRAN said:

Remove the aftermarket breather tube and install regular fuel line hose

I will give that a shot.  Could it be that the aftermarket hose is too narrow to allow adequate breathing?  

[FORMA MOTO]

It has a check valve. They are notorious for failing on those tubes

[EC-450f]

48 minutes ago, William1 said:

There is a one way check valve. Air can get in but not out. If your tank is full, the bike then in the sun, it will pressurize. Also may pressurize during slow riding due to engine heat.
Hold the bike vertical, slightly loosen the cap to let the pressure escape.

I tried to loosen it ever so slightly and as soon as it cracked open fuel started to seep.  That was even with a less then full tank.  i will double check the cap to make sure its not clogged.  

2 minutes ago, THE KRAN said:

It has a check valve. They are notorious for failing on those tubes

i will double check that.  thanks.  

[GCannon]

Check the underside of your fuel cap. the IMS check valve inside the fuel cap may be trapping fuel and when you remove the cap and tilt it up fuel drips out on to the tank. You may be able to drill a very small drain hole on the big bump inside the cap so the fuel will drain when the cap is installed. 

[EC-450f]

2 hours ago, GCannon said:

Check the underside of your fuel cap. the IMS check valve inside the fuel cap may be trapping fuel and when you remove the cap and tilt it up fuel drips out on to the tank. You may be able to drill a very small drain hole on the big bump inside the cap so the fuel will drain when the cap is installed. 

I will check that as well.  On a side note I see you have a plated wr.  My bike was plated in New Mexico originally but CA DMV said it needed CHP inspection.   i just had my CHP inspection yesterday and they said i should have no problem from the dmv so my fingers are crossed.  But in cali anything can happen....lol

[schrepracer]

2 hours ago, Ernest Chambliss said:

I will check that as well.  On a side note I see you have a plated wr.  My bike was plated in New Mexico originally but CA DMV said it needed CHP inspection.   i just had my CHP inspection yesterday and they said i should have no problem from the dmv so my fingers are crossed.  But in cali anything can happen....lol

Man, Hope you can get plated thru CA DMV. I have had a few friends get their bikes rejected and not plated in CA.

[EC-450f]

On 3/14/2018 at 3:34 PM, schrepracer said:

Man, Hope you can get plated thru CA DMV. I have had a few friends get their bikes rejected and not plated in CA.

schrepracer......  i must be lucky cause after a dmv inspection and two CHP inspections due to the officer not filling out the paperwork correctly i recieved my plates!!! Im stoked!!!!