Gas tank venting

I always get a strong gasoline vapour,,, as on left hand turns. The fuel spills out the vent hose,, as the gas sloshs over to the righthand (cap) side of the tank. Is there a quick fix here, for this ?? I wondered about a check valve, perhaps off an ATV or similar. I appreciate suggestions,,, thanks,,
Catmandu

One way check valve available from a Help Rack at most any auto parts store...Kirk at Vintage has these too. ~Alan

thanks,, Alan
I did look over the various PVC valves at our local auto shops,, but they were all a lot larger than the 1/8 vent hose I currently have on my tank. Perhaps I will have to step up the size of that hose,, to suit the smallest valve I can find.
Alan

i saw on a speedster build website (from the UK) a greeat idea for gas tank venting. simply bend the vent hose in an S shape so under hard cornering, there is no leakage, but still ablet o vent. it was done on the inner fender, so you wouldn't smell the gas too. pretty clever.

Common problem on Vs. Wonder why these check valves weren't put on at the factory during mfg.---Jack

I used to smell it every fill-up with the stock tank. Mine now vents from the highest point from the ground, on the midline of the car, and drops straight down through the frame-head gusset plate. No more odor of gas.

Alan, they have the 1/8" type on the Help Rack ~Alan

....um am I talking to myself ? :)

My solution is to skip the check valve, put a loop above the top of the vent line at the gas cap. Then run an additional 10' of 1/4" fuel line down the front wheel well to pass vapors out into the right rear wheel well.
After "enjoying" this issue for a number of years, I've also found that gas caps vary greatly in quality: some prevent vapor escape, many do not.
Cheers, Ernie

Is anyone using a vented cap instead of a vent tube?

Micael, yes, all Spyders do. We have the through-hood filler cap. Probably 98 % of Spyders have a vented cap, and since gas fumes linger, most front luggage spaces smell like gas. At least Speedsters have an option.

I wonder if I could remove the spring from my vented cap and open the tank's vent tube. Then run a hose with a "Help" valve to the outside.

Welcome back, Danny!
You could screw a nipple into the filler neck, below the spill tray, and run a line out the wheel well. Your spring would stay intact.

I use motorcycle/ATV one-way valves available from any motorcycle parts counter. I install them so they will allow air to enter the tank but keep gasoline from sloshing out the overflow/vent tube.

Alan M:

You were looking in the right place (the "Help" rack at your local auto parts store) but you were looking for the wrong part - you don't want a PCV valve....they're much too big.

What you want is a vacuum delay for a Ford Emissions system (they also use them on ATV's and some motorcycles, as Larry mentioned).

1/8" hose in and out. The device is a plastic gizmo about the diameter of a soft-drink cap and about 3/8" thick. The one I used was black on one end and white on the other (they're color coded for application - black/white is one-way only, no delay, rather than a slow leak (delay) for some emissions stuff).

I've heard them called vacuum delays, vacuum diodes, all sorts of stuff. I usually just wandered through a junk yard and picked up a handful along the way (they come in handy for all sorts of stuff).

Good luck.

Gordon
Organizer of Speedsters Meet Danny P. at Carlisle, 2008

Thankyou all, for your kind advice. My current vent line has a loop, just after the tank vent connection off the filler neck. Then it continues through the trunk wall,, and down to the skid plate. I am going to keep that arangement, and just splice in the checkvalve described. That should fix it.

On another topic,,, my new front disc brake kit just arrived !!
Alan