Gas Tank Venting

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Scrap
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Gas Tank Venting

#1

Post by Scrap »

Is there such a thing as gas gap that can shut off the vent when setting down on the jiffy stand? I usually keep a non vented cap in my pocket but I often forget to switch while riding. Has anyone ever done it as a DIY trick?
Thanks,
Sam
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Re: Gas Tank Venting

#2

Post by dirtydistrict »

Hi Sam, left gas cap is NON vented, right one is vented. That's the trick :-)
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Re: Gas Tank Venting

#3

Post by RUBONE »

Through 1964 both tanks are vented. It wasn't until the upper tank vent crossover line was added that the left tank became unvented. And the unvented caps are longer than the vented ones so that they do not interchange (if you try putting a unvented cap on an early tank it won't tighten, just spin). A 45 oil tank cap is unvented and would fit an early tank. But why? Being aware of the fuel level has always worked.
Scrap
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Re: Gas Tank Venting

#4

Post by Scrap »

It's been awhile since this bike was a daily ride. When I put it back in service I put a vented cap on the left tank and a non vented cap on the right. After a short time, the fuel stopped flowing. I switched the caps, same problem. I don't remember using two vented caps but I guess that's the why HD did it that way.
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Re: Gas Tank Venting

#5

Post by RUBONE »

What tanks are you using Scrap?
Scrap
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Re: Gas Tank Venting

#6

Post by Scrap »

Original 57 FL 3 1/2 gal. Tanks. This was a Mass State Police bike. Orig shut off rod, no upper vent line.
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Re: Gas Tank Venting

#7

Post by 1olchili50el »

Hey everyone, does anyone have a picture of the bottom of each cap, vented and non vented?
Thanks rich
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Re: Gas Tank Venting

#8

Post by panhead »

Here is a picture from the Gallery of an original vented cap:


Image
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Re: Gas Tank Venting

#9

Post by Wrong Road »

I believe you could plug the 2 vent holes on the underside with plastic, wood, glue, etc... I haven't tested this.
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