petcock on a ex-500
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Thread: petcock on a ex-500

  1. #1
    Certified Squid Array j5ive's Avatar
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    Aug 2007

    petcock on a ex-500

    on the ex-500 forum they advocate turning the petcock to off whenever the bike's not running "in case" it fails and you flood the carbs. But I know that even the zzr250's petcock doesn't have an off setting.

    So should I be turning the petcock to off everytime I shut off the bike?

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  3. #2
    Moderator Array Mighty Kentor's Avatar
    Join Date
    Mar 2004
    Mission, BC
    2004 R1, 2005 DL1000 V-Strom
    I wouldn't worry about it, unless you're transporting the bike.

    But that's just me.
    Reformatted to fit your screen.

  4. #3
    Registered User Array _ean's Avatar
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    Feb 2006
    boon town
    My petcock is always on

  5. #4
    Rockin' Ron Array Ron's Avatar
    Join Date
    May 2002
    Supa rocket spaceship!
    don't worry about it. It's vary hard and rare for the petcock to fail. If you took it apart and looked at it, you would see that it's quite solid first and second, it just provides a path for which straw in the gas tank to open up to.

    only worry about it for storage or transport as it can get gummed up or clogged then.
    "I'm gonna shine until my heart stop."

  6. #5
    Villin Array
    Join Date
    May 2008
    1990 EX500
    what they are talking about on is that a seal in your carb can go and let fuel drain into your crankcase... I leave my petcock on always though
    1990 Kawasaki EX 500

    I'm a newb

  7. #6
    Moderator Array TeeTee's Avatar
    Join Date
    Feb 2002
    Out to pasture in the 'Wack
    04 Kawi Z1000,
    A lot of the vacuum operated petcocks do not have an "OFF" position. But for bikes that do have an off position it's good to keep this in mind.

    However generally if a float needle gets stuck from a bit of crud it'll leak enough to flow out the overflow which has one of the tubes off the bottom of your float blow to extend down to around the swingarm region. So what happens is you end up with a wet spot under the bike that smells like gas when you put your finger to it and check. When you see that THEN it's time to start thinking about a carb cleaning or possible rebuild kit for it. Otherwise it's not a big deal.

    For the record I seldom remember to turn off the petcocks on my bikes with off positions and it hasn't been an issue more than once in all my years.
    A backyard mechanic without a service manual is just like a hooker without a lamp pole.... they are both in the dark.

  8. #7
    Registered User Array
    Join Date
    Apr 2006
    I disagree.
    The 'failing' petcock issue is Real. Certainly is true on 20+ year old yamahas
    Generally these work well as long as they are healthy, but it is coming up to 20! years old. They can and do leak, applying the full weight of the fuel in the tank to the poor little float vlaves in the carbs. Which also are not new.
    IF the bike gets parked for an extended period ( overnight even, if the problem is more than minor) Result is that the engine can fill with fuel ( certainly if the intake valve is open)
    Not good ! in any case.
    I suggest getting a decent Fuel on/off tap from a commercial lawnmower shop and insert it into the line between Petcock outlet and carbs AND remember to use it.
    Last edited by fred; 06-06-2009 at 08:49 AM.

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