Gas tank venting problem

[MikeT']

Saturday I was on a big ride and part of the way through the day my bike started spitting gas out the vent line. I extended the vent line off the rollover valve almost to the top of my snorkel. Is this problem with the rollover valve or the extended vent hose? My bike is a 09' and I thought they fixed this problem on the 09's. I am looking for the best fix for a snorkeled bike.

[repieces]

I'm not sure what the problem is, but mine does it as well (mine is snorkeled and the vents are extended to the top of the snorkels). But I've noticed that it only spits gas out of the vent when the motor is warm/hot and the fan keeps kicking on. But most of the time, my fan never comes on and no gas comes out of the vent. Have you noticed anything like that?

PS. Don't fill your gas tank to the top of the filler neck and then ride up a steep hill. I did this and gas was almost pouring out of the vent, going all over me and the grizz.

[MikeT']

Yea the bike was hot, but my tank was less than half full when it happened. Yes I made the mistake of filling it up in the neck one time and did it ever blow gas everywhere............ It is not a pressure issue, there was no pressure on the tank when i opened the cap. How in the hell is gas flowing out of a vent at the top of the tank?? I am considering putting it back stock, even though i am fully snorkeled, that part of the bike never goes under water for more than a split second.

[repieces]

Originally Posted by MikeT'

Yea the bike was hot, but my tank was less than half full when it happened. Yes I made the mistake of filling it up in the neck one time and did it ever blow gas everywhere............ It is not a pressure issue, there was no pressure on the tank when i opened the cap. How in the hell is gas flowing out of a vent at the top of the tank?? I am considering putting it back stock, even though i am fully snorkeled, that part of the bike never goes under water for more than a split second.

Yup, same issue with mine.....if you call it an issue. It may be how it works. Dunno. It probably did the same thing when it was bone stock but we never noticed it until it was spitting gas at us after extending the gas tank vent.....it could have been doing it all along.

[MikeT']

Well at least it won't be blowing back in my face in the stock form........

[AZ08Grizz]

I think what may be happening is that the vent tube is normally short and directed down. When extending the vent tube and directing it up it is allowing gas vapor to condense back into a liquid in the vent tube and this is blocking the release of gas vapor pressure until there is enough pressure to push the condensed liquid gas out of the line. Making the vent line as short as possible but keeping the outlet just above any expected water level should help eliminate this problem.

[repieces]

Originally Posted by AZ08Grizz

I think what may be happening is that the vent tube is normally short and directed down. When extending the vent tube and directing it up it is allowing gas vapor to condense back into a liquid in the vent tube and this is blocking the release of gas vapor pressure until there is enough pressure to push the condensed liquid gas out of the line. Making the vent line as short as possible but keeping the outlet just above any expected water level should help eliminate this problem.

You're probably right. But seeing that it doesn't happen on mine that often, and the stock vent location is too low for how I ride, I'll just leave it where it is. Good explanation though. Thanks.

[MikeT']

AZ08grizz you make some very good points, never had this problem before I snorkeled the bike. Actually If I am not mistaken won't the rollover valve work in reverse to keep water out? If this is the case then to extend this vent line is pointless

[AZ08Grizz]

Originally Posted by MikeT'

AZ08grizz you make some very good points, never had this problem before I snorkeled the bike. Actually If I am not mistaken won't the rollover valve work in reverse to keep water out? If this is the case then to extend this vent line is pointless

MikeT, I agree that there is probably no need to extend the gas tank vent. As you stated in effect the ball in the roll over valve keeps it closed to maintain a small amount of pressure in the tank. In the event of a rollover the weight of the fuel puts even more pressure on the ball to prevent leakage. In effect the vent is always closed unless it is venting out so water should never leak in unless you sink the bike in very deep water and in that event you have worse problems to deal with!

[MikeT']

Originally Posted by AZ08Grizz

MikeT, I agree that there is probably no need to extend the gas tank vent. As you stated in effect the ball in the roll over valve keeps it closed to maintain a small amount of pressure in the tank. In the event of a rollover the weight of the fuel puts even more pressure on the ball to prevent leakage. In effect the vent is always closed unless it is venting out so water should never leak in unless you sink the bike in very deep water and in that event you have worse problems to deal with!

LOL! No worries it floats.......... I will put it back stock and see how that works. Thanks