Topic: Leaky Petcock - help...please..

[caferacer550]

Hello.

I'm not sure how to solve this.
Hopefully, you good folks have an idea or have dealt with this before.

I have a 74 550 tank.
The petcock has a filter on the bottom and 2 outlets to the carbs.
And, its leaking.
Slightly when the valve is closed and a lot when it valve is open.
A lot being - 2-3 drops a second.
The portion of the petcock that contacts the tank seems to be fine.
Are there gaskets I should look for that my leak?
I plugged one of the outlets, because I only need one going to my carbs.
Could this be the problem? - I don't think so though.
Does anyone know if this particular part is prone to leaks?
When it leaks - the entire filter cup is wet.
As well as both the outlets.
There is no time when it does not leak.

Solutions I have been thinking of:

1. Coat the entire outside with a rubber type spray.
Reliability and looks could be a major problem with this.

2. Buying another petcock.
Don't really want to do that.

Ummmm.... 3. Ask the forum.

Any help at all would be great.

Thanks again.

[jaknight]

     You can pull the petcock apart and clean the rubber gasket that is behind the position lever; OFF, ON, RESERVE.  Be gentle with the screws holding it together; don't over torque them.  If there is a "bent up, crumpled" washer in there, don't flatten it out or straighten it.  The "waffled" washer/gasket was manufactured like that; it's supposed to be that way.  There is also a filter screen which you can clean and reposition.

     There are kits sold to rebuild the petcock.  This is fairly common on the petcock assembly.

     If push comes to shove, you can buy a new petcock.  They are available from David Silver Spares and many other sellers.  I had to replace the entire petcock on my '74 CB750 K4 because it was physically damaged (the petcock body was crushed) and the cheaper rebuild kit would not have done me any good.

     Temporary fixes aren't, in my opinion, a good way to go.  Gas leaks can become absolute nightmares instantly;.......... especially if you are smoking a cigarette while riding your scoot....

     ~ ~ ~ jaknight ~ ~ ~

[TwoTired]

Behind the petcock lever is a gasket with four holes in it.  It was rather soft rubber and made a good seal 30 years ago.
The filter bowl seats on an o ring that was also soft and compliant 30 years ago.

If these two components were replaced with new rubber, it might not leak.

I could be wrong, though.

[cbcoker]

notice where the gas leak is coming from. i am deealing with same issues right not and have had to replace most of the washers/o rings, little screws i've stripped in the process. not to mention having a petcock cup that's been torn to shreads by pliers. when in doubt replace gasket, buy another little screw and jb weld is your friend...s

[Philly550K1]

sounds like three possible areas to address.

1)the bowl and its little seal/gasket, 2) the two phillips screws attaching the petcock to the tank [and their critical fiber washers -- you need to take the bowl off to get to these], and 3) the four-holed rubber washer behind the on/off lever.

see if the bowl lets you tighten it any, and if that keeps the outside of it dry.

see if tightening the two screws stops the outlet dripping.

try tightening, flipping seals and tightening, and/or replacing as needed.

-jon

[caferacer550]

Thanks for the help.
The first problem has now been solved.
No major leaks.
But, now when the valve is in the off position - fuel still drips out one outlet.
I think it is the rubber washer inside the switch that is worn like TwoTired mentioned.
The one with 4 holes directing the fuel.
Could it be something else?
Have I over looked something?
Hrmmm...
Anymore thoughts would be appreciated.

[Philly550K1]

i ended up replacing my Quattroholio, as it's officially called, but i've heard of success with flipping it over and reassembling, and i vaguely recall tales of softening/swelling the rubber by soaking in ATF, boiling, or both...

-jc

[TwoTired]

i ended up replacing my Quattroholio, as it's officially called, but i've heard of success with flipping it over and reassembling, and i vaguely recall tales of softening/swelling the rubber by soaking in ATF, boiling, or both...

I also heard you can make one from hardware store bought neoprene sheet and a hole punch.  I might try this...

Cheers,

[martini]

Not sure if the Petcock on the 550 is the same or similar to the one on the 350 but I suspect so. I had similar issues with my 350. I bought a rebuild kit and replace all the rubber components - still leaked slightly. I took it apart again and wet sanded the flat side of the petcock lever which acts as the actual on/off valve. I had read that unless these are perfectly flat you might have leak problems. Anyway, I used a sharpening stone and very gently sanded the flat surface of the lever - problem solved. Hope this helps.

Martini