Fix a leaking petcock how to?

On my second 04 450sx and sure enough the petcock leaks both bikes and so did every toher 04-05 450sx. Replacement is over 80 bucks and will likely leak too in a year so is there some sort of material I could make my own out of?

maybe try another year petcock, not sure why the sx is so expensive

Edited by Fasz Kalap

Have owned a couple 06 and 07 models, will not fit or match.

Replace the oring for a couple of pennies

Look on-line in your areas (or an old fashioned phone book) and see if you have a company that sell's O-rings. Here in Denver THE place is called "Rocketseals"

I only point you this way as a generic o-ring will degrade with the gas over time, viton O-rings will not but they don't carry them at normal shops.

thanks for the replys folks but sorry it is not a oring, that would have been common sense to figure out. It is a round rubber like gasket, will try to get a pic up tomarrow.

Picked up a sx tank, and the petcock was leaking. It is a Mikuni petcock.

Took it apart, and noticed some caked in dirt. No orings to change, just a large waffle gasket. Cleaned off all the gunk inside, Put it back together and it stopped leaking.

We'll see...mikuni is just a few blocks from me, so if it leaks will see what they say.

There's two o-rings in there; one between the petcock assy and the tank, another in the valve.

Drain the tank, pull the two plastite screws out, and check out the little O-ring. It's viton (not NBR), ace hardware doesn't usually carry those. I ordered a bunch from McMaster.

On the bottom of the petcock there's two flathead screws holding the cover plate on. Pull those off, and pull the valve out. Clean it if it's dirty, then take that O-ring to your local hardware store and get a replacement. You'll be better off with a viton o-ring (gasoline resistant), but again, they usually don't sell those (just NBR). Throw some grease on it, put the thing back together and reinstall, shouldn't leak.

Fixed mine a few times now.

There's two o-rings in there; one between the petcock assy and the tank, another in the valve.

Drain the tank, pull the two plastite screws out, and check out the little O-ring. It's viton (not NBR), ace hardware doesn't usually carry those. I ordered a bunch from McMaster.

On the bottom of the petcock there's two flathead screws holding the cover plate on. Pull those off, and pull the valve out. Clean it if it's dirty, then take that O-ring to your local hardware store and get a replacement. You'll be better off with a viton o-ring (gasoline resistant), but again, they usually don't sell those (just NBR). Throw some grease on it, put the thing back together and reinstall, shouldn't leak.

Fixed mine a few times now.

There is no o-ring inside of the sx petcock. It is a thick waffle gasket with 4 holes in it. Not something you can pick up at the local store.

There is no o-ring inside of the sx petcock. It is a thick waffle gasket with 4 holes in it. Not something you can pick up at the local store.

I've got one of those in there too, that's used to isolate the ports in the valve. When you disassemble the valve, there's an O-ring that seals the petcock assembly and the valve part that you turn. Replace that O-ring.

I've got one of those in there too, that's used to isolate the ports in the valve. When you disassemble the valve, there's an O-ring that seals the petcock assembly and the valve part that you turn. Replace that O-ring.

Interesting, the one I have doesnt have an o-ring inside. Mine has a wavey metal washer.

Mine is off an '03 450 sx. Thought it was an '04. Same part number though..

Wave washer compresses the valve handle against the cover plate. O-ring sits on the other side of the land that slides into the assembly.

If it's missing... that's probably the cause of your leaks....

Took it apart, and noticed some caked in dirt. No orings to change, just a large waffle gasket. Cleaned off all the gunk inside, Put it back together and it stopped leaking.

From my earlier post.

i have this same problem with my 02 exc i took it apart and cleaned it ... thought the "wavy" washer was messed up guess its suppose to be wavy... anyway take the 2 screws out of the holding plate and there will be the wavy washer and behind that there is a white teflon? washer. So your saying take the pet cock lever out and pick the O ring out with a pick tool and this O ring is my problem?? Also someone must have done this previously to my bike because the 2 small screws are mis-matched.

I fixed a leaky petcock due to a slightly wavy (not flat) spot in the gas tank behind the petcock. I put a washer on one side between the petcock and the tank and that kept the petcock from smashing so hard and lifting the center away from the tank. Did this over 3 years ago and not a leak yet. Best of luck.

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