to vent or not to vent - that is the question

[MN_Bobber]

Newbie here (I did search first) - probably a silly question, but...

I have a 2.4 gallon sporty tank (sans the filler neck, cap, and petcock). The gas will be flowing into a pair of BS38s on my 78 motor. Do I need a vented gas cap or not?

Also, what determines this answer? Thanks everyone!

 

[Downer]

I'm pretty sure you do need a vent if it's a non vacum petcock. why? I think cause it's like a suction if there is no hole than the fuel in the lines wouldent move into the carbs kinda like a beer bong affect but not really sure that's my take on it

 

[jamesgs4]

yes you need a vent otherwise fuel will not flow out of the tank.

 

[jayel]

depends on what cap you what to use, some later model H-D tanks used a ventless cap they will have a small tube run up thru the tank into the bottom of the filler neck so it depends on what you put in for the filler neck, but one way or the other the tank will need a vent

 

[Punkskalar]

If the tank has that little vent line that is usually brazed shut, open it up with a drill bit and use a non-vented cap. Nothing sucks more than fuel spilling out of the cap and eating your nice paint job...

 

[MN_Bobber]

It the non vented type of tank pictured above (looks like the black tank). It has the vent line nipple under the tank. What gets connected there and where does it go?

Is that just an air escape for the vent in the filler neck? So, no need to run anything to it?

 

[jayel]

. What gets connected there and where does it go?

Is that just an air escape for the vent in the filler neck? So, no need to run anything to it?

nothing gets connected on Harleys, yes just a air vent, no need to but you could if you wanted to for some reason (open ended hose)

 

[MN_Bobber]

That nipple on the back is closed and not open. Therefor I need a vented cap...yes?

 

[alfredo]

That nipple on the back is closed and not open. Therefor I need a vented cap...yes?

Did you ever find a vented cap to fit your tank?

 

[MN_Bobber]

I did - $13.95 from the local HD dealer.

It did take a couple of visits though.