Topic: leak from fuel petcock

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Hi guys, I had problenms with gasoline leak from carburators drains but after some troubleshooting I found thAt the fuel cock (is this the correct name ?? ) is leaking in OFF position from the pipe highlighted (the 2 pipes should have the same  behaviour correct??)


Is there any guide to repair it ? thanks.

[flybox1]

Is it leaking OUT of the brass pipe, or from around where it is seated?

Those are just press-in outlets.  It can be gently tapped in deeper to hopefully seal, or, if the petcock is removed those can be heated and pulled out, cleaned, roughed, and with a little JB weld, pressed back in and sealed.

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is leaking out the brass pipe (I mean the gasoline flows into rubber pipes even if the cock is in off position). Thanks

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In few words is exetranlly proof but is not working inside where gasoline flows

[flybox1]

Petcock rebuild time 

[PeWe]

Strange, same pipe as came loose on mine. I replaced it with a new. I could hammer the pipe down, but I do not trust it. The petcock was only 2 years old, but fuel hose had been taking off-on-off-on many times and suddenly it followed the tight hose when removing it.

Maybe you can hammer it in to seat better?

[TwoTired]

Probably need one of these to rebuild the fuel valve.

[flybox1]

Strange, same pipe as came loose on mine. I replaced it with a new. I could hammer the pipe down, but I do not trust it. The petcock was only 2 years old, but fuel hose had been taking off-on-off-on many times and suddenly it followed the tight hose when removing it.

Maybe you can hammer it in to seat better?

^^^  this happened on my 550. 
I roughed up the brass a bit with emery paper, and tapped it back in, and it stopped leaking and pulling out.

[PeWe]

Strange, same pipe as came loose on mine. I replaced it with a new. I could hammer the pipe down, but I do not trust it. The petcock was only 2 years old, but fuel hose had been taking off-on-off-on many times and suddenly it followed the tight hose when removing it.

Maybe you can hammer it in to seat better?

^^^  this happened on my 550. 
I roughed up the brass a bit with emery paper, and tapped it back in, and it stopped leaking and pulling out.

Also same pipe, the left one when looking at the petcock when tank is in the bike?
 It might be a looser clearance  on that side when making the petcock.

[Bankerdanny]

Petcock my friend, that piece is called a petcock.

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Thanks.has any one pics or procedures to perform the job?thamks

[flybox1]

A simple task.  Dont really need to remove it from tank, but it might make it easier.

Empty tank.
remove bowl from petcock (two screws hiding in here removed will allow you to take it off the tank)
clean out and replace screen.

IIRC, two screws on the face of the pet will allow you to remove the valve and clean it all out.
replace internals.
Put it back together w new valve and bowl oring.

[PeWe]

The 2 screws have x-heads. First thing I did was to replace them with allen head screws I had home. Easier to tighten, the X heads need the perfect screwdriver. There are 2 fiber washers on those screws as well. Work as gaskets. Really tight fit when new.

You will replace the o-ring between petcock and tank or the entire petcock?

[Bodi]

Sounds like the leak is just a "normal" petcock-off leak, not a problem with the brass nipple fit?
That's generally from the rubber disc wearing out, the little protrusions wear down with use and eventually don't seal so well. Replacing that is the answer, they are available. If the mating metal part is worn as well - the handle piece - it can be polished/lapped with solvol or brasso to be flat and shiny. You should lap it on a flat surface so it doesn't get dished.
The spring washer can be gently bent to be a bit more serpentine, increasing the spring pressure.
There were versions of that petcock with screws holding the cover on, and ones with rivets. The rivets can be removed by carefully drilling the heads off, and then their holes threaded for installing screws.

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Thank you guys for your answers:
I opened the petcock today and I found inside some metal flash or drool (don't know correct name) around one hole.
Why there is such flash ? is the petcock broken ? or I can simply replace the gum ?


Currently I'm experincing leak from all the carburators (from drains) when the motorbike is stopped for at least one day.
Another question is that I would like to know if the needles of carburators are capable to shut off the gasoline in off condition of motorbike or this problem should not occour even with a not working petcock.

Thanks

[TwoTired]

Why there is such flash ?

Either a flaw or someone tinkered with it.  Remove the sharp bits and try a new seal (or gum).  The seal shouldn't be sliding over that distorted area and ought to work properly.  Or, you could buy a new valve.  I prefer to fix broken things, myself.  But, current vogue is to replace with new, that which is old, or not working as it once did.  This is the way consumerism is being guided.

Currently I'm experincing leak from all the carburators (from drains) when the motorbike is stopped for at least one day.
Another question is that I would like to know if the needles of carburators are capable to shut off the gasoline in off condition of motorbike or this problem should not occour even with a not working petcock.

In the ideal case, the float needle valves should block inflow of gas, even with a faulty petcock.  But, it is common that they aren't 100% reliable.

Do check if the fuel tank is clean and rust free.   It doesn't take much to block the float needle valve open and cause a leak.
Other possibilities are:
The float needle and seat are worn.
The float height adjustment is wrong (check using the "clear tube Method").
You might have cracks in the stand pipe/ overflow tubes in the carb cowls.  (Though it seems odd all four would crack at the same time, it's possible.