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Gas leaking out small hole at bottom of petcock on 2002 Harley Dyna

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If its the automatic type controlled by the engine then the diaphram is puntured

Posted on Jul 07, 2010


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Leaks gas from under gas tank 2002 road king

You have a hole in your gas tank or your gas lines are dry rotted. If your fuel injected, you should replace your hoses. If it is carbureted, you could have a bad petcock get yourself a bar soap, and we think it's leak in. Just pack it with soap. It's a leak stops. That's where it is. Before you do anything. No decrease it and clean it, so you can see where the leak starts from

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Pet **** @ fuel line gas leak

Hi Anonymous, yes they do. You can take it apart and put a rebuild kit in it or buy a new fuel valve. Good luck

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1995 wide glide gas leaks below petcock when bike is running

Hi Anonymous, for more information about your question please visit the websites below. Good luck and have nice day.

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What causes gas to leak between petcock & gas line, fuel injected

If it is fuel injected it does not have a petcock per say. If it is carbed then it may be a gasket or seal in the Fuel Petcock. If it is injected then it is an 06 not an 05. If that is the case then it is an o-ring on one of the fuel lines under the tank that need to be replaced. Or you may need to replace one of the fuel lines on either version it could be from a crack or hole in the line.

Feb 27, 2011 | 2005 Harley Davidson FXDL - FXDLI Dyna Low...

1 Answer

Gas is leaking from the peacock valve under my gas tank seems to be coming directly from the bottom,what could cause this?

There's a gland nut that holds the petcock into the tank and pulls it up against the seal. Try tightening the nut. But, in all probability, it's the vacuum diaphragm in the backside of the petcock.

Harley went to a vacuum operated petcock in 1996 and they've been a pain ever since. The diaphragm gets a small hole in it and leaks gasoline or quits opening leaving the rider stranded.

Now, You can repair the petcock if you wish. Get a large funnel and an empty gasoline can. Loosen the petcock and allow the fuel to run out around the nut, catching it in the funnel and directing it into the gas can. Once empty, take the fuel line and the vacuum line off the petcock. The vacuum line is the small line on the backside. Take the petcock out of the tank. Look on the backside and there are four small screws. Take them out and carefully take the back plate off the valve. You'll see a diaphragm, a spring, and needle. Take the diaphragm and hold it up to the light and gently stretch it. You'll probably find a hole. You can get a replacement diaphragm from you local dealer. Reassembly is the reverse of disassembly.

Personally, I'd rather replace the vacuum operated petcock with a high quality manually operated petcock such as Pingel. The OEM petcock will fail on you and leave you stranded with a full fuel tank and an empty carburetor. The Pingle won't. Just install it, connect the fuel hose, and plug the vacuum hose.

Good Luck

Sep 12, 2010 | 2000 Harley Davidson FXDL Dyna Low Rider

1 Answer

The small hole behind the petcock is leaking gas is the diaphram bad or is it pressure problem from maybe the gas cap

It's a diaphragm problem most likely. These things are notorious for giving problems. I always suggest people upgrade to a high quality manually operated petcock like a Pingle.

But, if you want to keep you vacuum operated petcock, you'll have to drain the tank of fuel. Get a large funnel and an empty gasoline can. Loosen the petcock with the large funnel to catch the fuel and guide it into the empty can. Unplug the fuel line and the vacuum line. Remove the petcock from the tank.

On the backside of the petcock, there's four small screws. Remove the screws and carefully take the back off the petcock. There's diaphragm, a needle and a small spring behind the plate. Hold the diaphragm up to the light and gently stretch it. Look for holes. You can get a replacement diaphragm from your local dealer.

Good Luck

Sep 10, 2010 | Harley Davidson FLHR - FLHRCI Road king...

1 Answer

My 1998 Dyna has a small leak or drip coming from petcock

Sounds like you have a hole in the vacuum diaphragm that opens and closes the petcock. This is one of the problems with the vacuum operated device. The other problem is that sometimes they don't open and you're left stranded with a full tank of gas and not a drop in the carburetor. I changed to a manual operated petcock. Personally, I'd rather have a Pingle petcock than another vacuum operated Harley petcock. If you do change to a manual operated petcock, don't forget to plug the small vacuum hose.

If you want to keep your vacuum operated device, I think you can buy a replacement diaphragm. You will have to drain the tank and remove the petcock. There are four small screws on the backside. Remove the screws and the backplate will come off. The diaphragm and a sping is all that is in that section of the petcock.

Mar 31, 2010 | 2000 Harley Davidson FXDWG Dyna Wide Glide

1 Answer


Sounds like you've got a vacuum leak somewhere. Either your intake seals or the carb seal is leaking air. Have you replaced the air filter housing? On the Evolution and later engines, the carb is designed as a "spigot seal" type carb. In other words, it just pushes into a seal instead of bolting on like the older carbs did. This means that the carb has to be aligned correctly or an air leak can occur around the seal. The air filter assembly is what holds the carb. into the seal and aligns the carb.

If you haven't messed with the air filter assembly there is one other thing that I've seen cause this problem. Your bike has two vacuum operated devices on it. One is the VOES switch and the other is the fuel petcock. The VOES switch is part of th igniton system and the petcock is the fuel valve on the fuel tank. The vacuum comes from either the carb or the intake manifold and is routed to the devices by a vacuum hose. Make sure this hose in connected to all three locations and has no holes in it. The vacuum hose to the petcock is on the backside of the petcock and the VOES is located on the bottom of the frame top tube under the fuel tank near the carb.

I have seen the vacuum operated petcock cause a vacuum leak in at least one occasion. Normally, when they go bad they just shut the fuel off to the carb and the engine won't run. But, I did have one that caused a severe vacuum leak and the bike acted exactly like you're describing. I took the petcock out of the tank. Drain the fuel first, not easy to do with the petcock being vacuum operated. I got a large funnel and held it under the petcock while I slowly unscrewed it. Once you have the petcock out, you'll see four small screws on the back side of it where the vacuum hose connects. Remove the screws and check the diagraphm behind the plate. Be careful, there is a small spring behind the plate. Take the petcock apart carefully so you can remember how to properly reassemble it.

Personally, I would eliminate the vacuum operated petcock and replace it with a high quality manual operated petcock. Like I said earlier, if they malfunction they usually shut the fuel off to the engine. There you are, a full tank of fuel but none to the engine. I'd replace it with an original Harley unit for a 1995 or earlier bike or a high quality aftermarket unit like a Pingle.

You need to find this problem before you ride the bike too much. The lean mixture resulting from a vacuum leak will cause the engine to run very hot.

Oct 20, 2009 | 2002 Harley Davidson FXDWG Dyna Wide Glide

2 Answers

1200 sportster gas leak

You will need a new petcock. The internal seals are gone.

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