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Discussion Starter #1
I seem to be learning things the hard way. Forgot to shut off my petcock on friday...came out today and saw gas all over the ground. One of my spark plug wires was physically up against the petcock and is now inflated and soaked in fuel.

Well i needed to replace the wires anyway. Time to get it done i guess....

,mike
 

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Discussion Starter #6
Should have but in florida it gets crazy hot and i've been told the pressure can build up enough to make it leak. idk how accurate this is but it seemed feasible considering the past 2 days have been horribly hot and my bike was out in the sun.
 

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Should have but in florida it gets crazy hot and i've been told the pressure can build up enough to make it leak. idk how accurate this is but it seemed feasible considering the past 2 days have been horribly hot and my bike was out in the sun.
I do not think I can buy that. Perhaps other Florida members or Ceal (the resident expert on grande calliente) can chime in.

What I do know from experience, the OEM petcock is completely open before 2 inches of vacuum. I personally tested mine. If any part of the diaphragm 'nipple' or its bore isn't smooth, you could have a dangerous situation. The diaphragm, spring and o ring need to be in good shape.

HTH,

edit-I have never turned mine off.
 

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FREEBIRDS MC CENTRAL NY
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When the bowls fill floats should shut gas. flow off.either float needle is dirty and sticking or floats need adjusting
 

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Just a regular guy
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I have never turned mine off, I live in North Florida, I have never had an issue with the petcock leaking, from heat or any other reason. If you rebuilt it 2 weeks ago, then something isn't fitting correctly.
 

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FREEBIRDS MC CENTRAL NY
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Sorry i thought the gas was coming from the carbs
 

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Chasin' the blacktop
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The vacuum activated petcocks most of us have aren't needed unless our float needles get dirty and hard with age. Even with a good petcock a bad float allows the fuel in the line below the petcock to flow in diluting your oil at best,,, one half ounce at a time (about what fills your fuel lines). Since our engines get hot when running this tiny amount of fuel that can leak past a bad float will evaporate through the crankcase vent so many of us with good petcock but bas float needles will never notice the difference but we're slipping a little fuel past every time we stop the bike. It's time to repair your needles/floats in your carbs and replace the vacuum diaphragm in your petcock although Wolffies carb blowback seems to help if your problem is simply dirt preventing the float needle from closing but you still need to rebuild your petcock which takes 15-20 minutes.

Our tanks have an air vent tube coming out of the rear and tucking under the seat so hot fuel tanks with expanding fuel shouldn't force fuel past the needles in the carbs (unless it's kinked).

Float needles are expensive but sometimes we need to just get the part assuming the blow back method doesn't clean thing up.
 

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It gets a lot hotter in Phoenix, AZ. Mine does not leak, though it has a couple of times since I bought the bike new. I had to replace the seals/diaphragm in it. Mine was leaking around the lever itself, not into the fuel line. When I took it apart, I found melted rubber parts. Ethanol strikes again. When working properly, the petcock does not need to be messed with. It is always off. Vacuum from the front carb is what opens it. I used to didn't like that kind of petcock, but they can save your carbs, especially since the advent of ethanol gas. If you forget to turn off a manual petcock, as gas/ethanol evaporates out of the float bowls, more runs in, and it continues to evaporate, doing more and more damage. With a vacuum petcock, when the fuel in the carbs evaporates, no more can get in.
 

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If you forget to turn off a manual petcock, as gas/ethanol evaporates out of the float bowls, more runs in, and it continues to evaporate, doing more and more damage. With a vacuum petcock, when the fuel in the carbs evaporates, no more can get in.
Damn, that would have been another answer for kc and Merc.
 

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It's not an answer. As you burn fuel more runs in too. What are we going after?
 

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Live in N.Central Fl,just below Ocala.Temps generally 90+ but I store my Vulcan in my shop/garage...when I park it in the (hot) sun I leave the Petcock "on"...I see no leak.
 
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