Petcock Assy Drawing-Vent Hole Leaks- Mod Valve?

Hi All,

Fired it up yesterday for the first time and sounded good. But I have a massive leak out the vent hole of the petcock when in prime position. I am sure I have improperly reassembled the petcock with the rebuild kit. the Clymer Manual petcock image does not even show the plastic sandwiched plate!

It did not seem I could put the diaphragm valve between the plastic plate and the petcock body due to stack up so I put it on the outside of the plate. Obviously wrong. Is there a particular clocking position for the vent hole on the plate? Towards or away from the petcock body? Which 90 degree orientation?

Is there a website link that has a clear image with things in their proper assembly order & orientation?? A procedure anywhere? I completely cleaned the valve so dirt is not an issue. Searching web but so face no luck.

Has anyone ever converted/modified the OEM vacuum petcock to a manual petcock with some strategically placed epoxy, successfully?

TIA,

Bill

Pics?
Steve

Which model and year bike do you have? Kawasaki has used a bunch of different petcocks.

It has been a while since I have rebuilt one, but as I recall yhe order on mine is petcock body, plastic spacer, diaphragm, cover with hose barbs. It does matter how the plastic part is installed on mine, as there is a locating pin.

Turning a vacuum petcock into a manual one is very easy. Remove the vacuum hose and cap the vacuum port on the carb. Prime become On and the other positions become Off. However, this will not solve your leaking problem.

The diaphragm plate on my 81 650-CSR has little pins that align with holes on the petcock body & diaphragm cover, so it's kinda hard to install it wrong. Also, the plate is sandwiched between the 2 faces of the diaphragm, so 1/2 the diaphragm has to be installed thru the big hole in the plate prior to installing the diaphragm assy onto the petcock.

It is an '81 GPZ 550. martin, Your post suddenly makes sense. I knew I had gaskets on both sides of the plastic plate when I removed it. However, now that you say that I think one side pulled off of the 'diaphragm assembly' and stuck to the body side of the petcock. Which made me think I was missing a gasket and the diaphragm was improperly assembled with 2 gaskets.

The plastic plate has a large 'counter-bore'. Does it face away from the body? Meaning I need to 'feed' the gasket through the hole in the plastic plate from outside the plastic plate through to the body side of the plastic plate?

There is a little vent groove on one face of the plastic plate. This is where the gas was shooting out. Is that installed on the body-side or the spigot side when sandwiched? I had it on the body side (which would be the 'wet' side, I am now guessing it should be the spigot side...?

If this doesn't get it I will post photos.

TIA,
Bill

The groove is on the plunger side, facing the body. Also, if you look at the plate, the side facing the vacuum cover has a larger round well for the round metal spring plate of the diaphragm. And as already mentioned, there should be alignment pins on the plate & it can only be installed one way. Maybe yours is different or the pins have been broken off. ???
From the diagrams at partzilla your bike should have the same diaphragm assy as mine.

2 alignment pin holes are near the screw holes closest to the base of the petcock body.

Hi Martin,

Your photo was helpfull although your photo did not show the center block at all, the bit of info I was looking for was how to position the gasket. One layer on either side of the plastic block. Works OK now although it did leak a bit at one point it stopped. Seals & O-ring probably have to get friendly with the mating surfaces.

Thanks all,

Bill
Now on to the next fix... front master cylinder rebuild - fraggin brake switch..

New thread please.
Steve

SweetGPz wrote: Your photo was helpfull although your photo did not show the center block at all, the bit of info I was looking for was how to position the gasket. One layer on either side of the plastic block. Works OK now although it did leak a bit at one point it stopped. Seals & O-ring probably have to get friendly with the mating surfaces.....

The pic is from a couple of years ago when I cleaned the thing with PineSol.
If still problematic, maybe post a photo of the plate? It could be that yours is different from mine or something.
On my fuel tap the plate & diaphragm can only be assembled & fitted to the petcock body one way.

The 81 GPz 550 fuel tap assy has a different part number than the 81 650-CSR, but the diaphragm assy should be the same. It's possible the part number for the diaphragm does not include the plate, so I guess the plates may not be identical. ???

You should be able to get a rebuild kit for petcock. They were plentiful awhile ago. The plastic plate does not come with it.

There are little weep holes that allow leakage to exit, rather than go directly into the vacuum line. I think the weep hole goes on bottom.