Petcock leaking...cold weather the culprit?

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njcafe84

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I just rebuilt my petcock 2 years ago...could the freezing temperatures be the reason why it is running even with the engine off.

Its a constant drip if I disconnect the fuel line from the carburetor side but its dripping enough that its begun to leak out of my air filter.

is a new rebuild kit in my near future?
 
Todays fuels can destroy o-rings and seal in no time. I have been using this stuff for years and have had no issues with rubber parts leaking or going bad. Yamaha makes and sells it.
 

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I've seen a documentary requarding ethanol gas in Oregon specifically at marine's and I was shocked at how badly the fuel line's had degraded.

Where I live in Canada, most of the gas station's state they MAY have ethanol is the low and med grade's and even the premium. We have one supplier who stated they have NONE in their 94 octane premium. I run this in all my bike's.

This will keep ya busy

https://www.google.ca/#q=ethanol+degrading+fuel+lines
 
You're lucky if you can get ethanol free stuff. Where I am only airplane and boat filling stations have it. They'll sell it to anyone, but you have to fill a container. You can't directly fill a street vehicle.

Fuel stabilizers are impractical for me. Often I do 400 miles a day. I'd have to carry a jug on me. Meh, I guess I could. A lot of stabilizers come in small containers.
 
The stuff I use also comes in a 3oz bottle too enough to treat two tank fulls.
 
Could I just replace the gasket behind the knob (the round one with holes) or do I have to do a total rebuild kit?
 
Most likely it the diaphragm o-ring that is causing the petcock to let gas flow when it's off.
 
2G2-24534-00-00 this part number xschris?

Is it just a generic o-ring? Partzilla wants $6 just for that part without shipping
 
Could be the spring, experienced shrinkage. or that the only rebuild kit available has a know issue. I resolved by putting a smaller O-ring behind the new O-ring from the kit. That created a better O-ring mating, than I had previously. We are not the only bikes with this model petcock. that's how I came across this tip. Look at my Pics, this worked for me.
http://www.xs400.com/media/albums/599/

You can also put on a fuel shutoff, and that will protect everything south of the carbs. Now you have to smell your oil cases, to make sure you don't' need a oil change.

http://www.xs400.com/forum/showthread.php?t=8033 This is the thread I added too, Page too shows everything else I was worried about.
Tobie
 
Not trying to hijack the thread, but i also have a petcock problem.. at least i think i do. I have an 82 xs400j Maxim and i noticed a little bit of what looks like engine oil leaking out. not a lot just a couple drops. Does anyone have any idea what this could be?
 
Funny thing, one of the 2 or 3 links was specific to Maxims, Your not hi-jacking, if your topic is the same as the subject. In fact, it might help us, help you, if you had the chance to search for previous issues in the same thread. Then you might have noticed that one link was a Maxim link.

http://www.xs400.com/forum/showthread.php?t=8033

Page 2 of that link goes to a Maxim website, I have chatted with that moderator on my solution. You will find that he will point out the original O-ring was wider, and hollow. It allowed for the inconsistance standards that was getting shipped out to Yamaha. Now you can not find a hollow O-ring any where, and the new O-rings, just doesn't stand out enough for a proper seal.

This link has my solution, I ordered the O-ring from Amazon.
http://www.xs400.com/media/albums/599/

Tobie
 
i am having a similar issue. i think i have traced the problem to an old dried out vacuum hose from the carbs to the petcock. It wasn't sealing air tight at the connections so the air pressure was not right and everything was messed up.
 

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