[pry3abet]

So I went for a little ride and filled up, then when I got home I let the bike sit for an hour and changed the oil. I opened up the gas cap so I could add some seafoam and it popped and gas shot out everywhere. What is could be causing all this pressure inside the tank?

 

[stroguy]

Bad gas cap? The seal should be good...very good, but the cap should have a pressure release point. Maybe it is faulty or was assembled incorrectly.

How much do you fill the tank? I add just enough fuel that it is lapping at the lower ring of the filler neck.

 

[kraaazymike]

Do you fill past the neck filler line of the tank? If you do, heat can cause the gas to expand more into the filler neck and when you open cap it can splash out. This can also get into you vents and cause venting issues. Try not to overfill the tank if you are.

 

[11Stryker]

Fuel comes from cold underground tank, then into your fuel tank, where if it is a warm day, the fuel expands. Now if you overfilled, then this answers your problem, but if not, then you have a venting problem.

 

[11Stryker]

Maybe you did what I did once. Here is the thread http://www.yamahastarstryker.com/21...-after-being-parked-found-gascap-too-far.html

 

[dblshock]

on a hot day you can hear the gasoline boiling in my 680 Rincon ATV..scary.

 

[pry3abet]

Being that it was inly 60 degrees today and I never had this problem at all last year and I fill my tank up to the same level every time, i am going to go with perhaps a venting issue. I did have the take off a few weeks ago when i put new turnsignals and headlight on. I cut the wiring harness and tucked it up under the tank instead of stuffing it inside my new light.

 

[pry3abet]

Also, is there any problems with me riding the bike till i figure out what is the issue?

 

[cambridge]

Fuel comes from cold underground tank, then into your fuel tank, where if it is a warm day, the fuel expands. Now if you overfilled, then this answers your problem, but if not, then you have a venting problem.

Dead on.

You can fill your tank at a gas station and if you fill it to much, when you drive off the gas will start to come out from under the cap. You have a cold gas tank filled with gas, as you move the outside of the tank warms up. This causes outside pressure pushing on the tank causing the inside to contract.

Just take a water bottle filled with water and start to squeeze the bottle. This is what happens to the tank. As the fuel empties the air in the take is still compressing. Once you open the cap outside air rushes in.