mysterious petcock mystery

[tiggen]

Took my tank off the other day, put it on a shelf. Came back the next day to find a pool of gasoline below it. Fuel valve was set to OFF. I put it back on the bike and hooked it up to the lines until I could get to it today.

Today I took the lines off and waited. Nothing, not one drop. Moved the valve to ON...nothing coming out. Moved it to RES, nada.

So why did it leak the day before? And why won't it come out when the valve is ON or RES?

And why is the tank so $%^&))%^ impossible to drain??!!

[kkim]

the diaphragm in your petcock possibly is flaky. it is operating correct, now. it should not flow any fuel when there is no vacuum applied to the back of it. there is a smaller vacuum line attached to it along with the fuel line.

perhaps the gas that leaked out was just the residual in the fuel line. was the fuel line left attached to the tank?

apply vacuum to the vacuum tube (suck on it) and the gas will flow through the petcock or dump the gas out the fill hole by turning the tank upside down when it's removed from the bike.

[CZroe]

Someone here had pictures of their defective petcock. The defect was that the plastic ring that seals against the petcock wasn't a full ring (a chunk was missing). IIRC, there was an issue replacing it because it's part of the petcock assembly or something and not something that can be ordered on its own.

Edit: Looks like it was adouglas / Andrew.

[coondog]

inside, attached to your petcock base is a filter, looks like a four inch straw with a mesh top. it holds enough to leave a tiny puddle once vacuum was broken by placement on another object.

[tiggen]

Originally Posted by kkim

perhaps the gas that leaked out was just the residual in the fuel line. was the fuel line left attached to the tank?

apply vacuum to the vacuum tube (suck on it) and the gas will flow through the petcock or dump the gas out the fill hole by turning the tank upside down when it's removed from the bike.

No, fuel line wasn't attached. Will try the vacuum with the mity-vac.

Originally Posted by CZroe

Edit: Looks like it was adouglas / Andrew.

Well, I didn't open it up, but if it happens again I will look for this.

Originally Posted by coondog

inside, attached to your petcock base is a filter, looks like a four inch straw with a mesh top. it holds enough to leave a tiny puddle once vacuum was broken by placement on another object.

I'm thinking this is what it was, yet I tired to get it to do it again and got nothing. And when I took the petcock out the "straw" was full. Guess it's not that big of deal as long as gas isn't just falling out when everything is connected.

Thanks for the responses!

[choneofakind]

Originally Posted by CZroe

Someone here had pictures of their defective petcock. The defect was that the plastic ring that seals against the petcock wasn't a full ring (a chunk was missing). IIRC, there was an issue replacing it because it's part of the petcock assembly or something and not something that can be ordered on its own.

Edit: Looks like it was adouglas / Andrew.

Does that plastic ring look like a disk about the size of a quarter (roughly) with 4 equally sized holes in it and cant be ordered on its own? That was leaking in my petcock. I replaced it with the same part from a '86/'87 ninja 250 which can be ordered on its own for like $4. Took it to the shop and had them pressure test it. Works great. No more leaky petcock

**edit**
looked at the link. I guess I'm not talking about the same thing. take off the knob on the petcock and check out the piece I'm talking about. Mine had a chunk missing. Just thought I'd suggest that as a possibility because if thats the issue, it's a cheap fix
**/edit**

[kkim]

diaphragms can be replaced in the pregens, but the newgen petcocks are different and cannot.