Gas cap vent / petcock trouble

[Emerica1975]

I’m having trouble with my gas cap not venting and I’m wondering how that can be fixed without having to get a new cap. My cap looks fine but I know it’s not venting. Also my petcock on my 55’ st only works sometimes then it stops letting gas flow until I wiggle it. Does anyone make a decent petcock that actually works. I’ve gotten a few new old stock Superior brand ones and they seem to be worse than the ones Harley made back in the 1950’s.

[Mutt]

ALL repop petcocks are made in the same Factory in Tiawan. The sellers know they dont work, but continue to sell them any way. The petcocks use cheap rubber, not made for todays fuel. How do ya know your gas cap isn't venting?

[Emerica1975]

When I get done driving my bike I can hear a hissing coming from my gas tank and when I open the cap the hissing will stop. And the bike seems to run better with the cap loose. And just so I’m clear the bike with the bad petcock is different than the one with the faulty petcock.
Will the big twin petcock (62125-55b) thread into a hummer tank?

[Mutt]

yes. this is what Ive been using for many years. They always work

https://www.jpcycles.com/product/drag-s ... _id=964752

[Emerica1975]

I just ordered a couple of those petcocks from J&p. Thanks! Any ideas on how to fix the gas cap vent? Or do they actually have a vent in them? I was thinking about just drilling a small hole ( real small) in the cap. But i hate ruining old original parts even if they aren’t working properly.

[Mutt]

they have 2 vents. Turn your cap over. You'llm see 4 vents on the edge 90º apart and 2 by the outside edge of the cup. You can clean them with compressed air

[Emerica1975]

Thanks for the direction. I found the vents. The 2 on the base of the cap had an ancient cork gasket that had become one with the metal blocking them and then another cork gasket ontop of it. The 2 at the base of the cup looked good. Thanks again Mutt!!