How Do You Stop a Leaky Gas Cap?

[5-7HEAVEN]

I have a goped tank feeding my 460 engine on "The Iron Dragon". A 4-liter reserve tank is plumbed into the fuel system, controlled by a standard petcock. When this valve is opened it automatically fills the g-tank in a few minutes. The system works very well, but I must remember to shut the petcock or the excess fuel will keep spurting out the cap's vent hole.

Once I forgot to close the petcock while riding, and this huge cloud of gas followed my bike, waiting for a spark to ignite the mixture.

My reserve tank is not vented, but my goped tank is. If I plug the g-tank's cap and vent the reserve tank, the petcock has to be open at all times.

I'd rather not have the valve open, except when it's time to fill the goped tank.

Aside from being vigilant and shutting the valve before the g-tank overflows, how could I cure this leaking fuel problem?

Oh yeah, if the goped tank is full it dribbles out of the vent hole until the fuel level drops maybe one inch.

 

[Hawaii_Ed]

Hmm, my water bottle has a small rubber stopper with a slit in the vent hole. It allows air in to relieve the pressure when you suck on the straw, but will not allow anything to flow out when you invert it...It is really pretty small, maybe take one of those, enlarge the vent hole if needed, and pop it in?

In emergency medicine we use a similar device (bigger) to allow pressure to escape off a collapsed lung, but then can not draw in air from the outside.

I can take a pic of my water bottle lid if you want to see it

 

[Pirate88179]

I agree with Ed's assessment. When I went to the the local lawnmower shop to get a used tank for my 2 cycle HF clone motor, the guy took time and explained to me everything I needed to know about these tanks. One of the lessons was, yes the tank needs to be vented but, you can't just use any lawnmower cap. It has to contain a one-way valve that allows air in, but no fuel can get out. This problem arose since I found the tank I wanted, but we searched for like 20 minutes to find the correct cap that not only fit it, but had the one-way valve. This way, he said, I could lay the bike over (hopefully not) and no fuel would come out. I hope this helps.

Bill