Leaky LC-4 petcock question for ya

Discussion in 'Thumpers' started by micio, Apr 1, 2007.

  1. micio

    micio stress kitten

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    I've got a slooooow leak on my '02 Duke ll petcock (it's the Mikuni CK-69 '96).

    I haven't had it apart yet but I'm guessing that there's a lil' seal in there that needs replacing. Trouble is, I can only find the petcock assembly complete for about $50...

    Anybody know if an automotive gasket will cure it? :ear
    Or do I need to man up and buy the whole thing?
    #1
  2. bmwktmbill

    bmwktmbill Traveler

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    I took mine off and cleaned it and put in a new O-ring.
    It leaked just the same. It is a bad design, take it apart, you will see.
    Better to cut an old piece of fuel line with a plugged end and stick that on the petcock outlet when the tank is off.
    IMHO.
    bill
    #2
  3. micio

    micio stress kitten

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    Thanks, Bill. If cleaning and a new o-ring won't fix it, and it gets to be real bad, I'll kick down for a new one.
    #3
  4. lvdukerider

    lvdukerider Las Vegas Nevada

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    The one on my 00 Duke II just started leaking last week. I guess the 50 bucks I spent to order a new one wasen't wasted then.
    #4
  5. ktmMike

    ktmMike Long timer

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    Lengthen the fuel line a bit and add an aftermarket in-line petcock, then just leave the stock one open.
    #5
  6. lvdukerider

    lvdukerider Las Vegas Nevada

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    I hear what your saying but mine is leaking around the outside of the part that you turn. Plus I just picked up the new one up from my dealer today. Thanks for the idea though.
    #6
  7. bmwktmbill

    bmwktmbill Traveler

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    The petcock can leak two ways, one is to the outside and the other is through the petcock.
    If you take one apart you will see it is built like a bung. There is an o-ring that keeps it from leaking to the outside. That can be replaced to stop that problem.
    I can't see how to fix the through leakage but someone might know more.
    Bill.
    #7
  8. biensur22

    biensur22 litigious poster

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    Sorry for the thread revival, but anyone ever use the raptor petcock on the LC4 tanks? I know a lot of people broke the petcocks off their tanks on the 640As, so there must be a decent replacement. Both sides of mine lead on the outside, but replacing the o-rings didn't fix the problem.
    #8
  9. bmwktmbill

    bmwktmbill Traveler

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    Did you use metric o-rings?
    b
    #9
  10. Reinhold

    Reinhold No, not Messner

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    I just eliminated mine. Put a blocking plate on where the petcock was on my Adventure. Ran a T connector with fuel line from the tank crossover to the carb. Works like a damn!
    #10
  11. biensur22

    biensur22 litigious poster

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    What? no fuel pump? What do you do when you have to take off the tank? Ride 300 miles then pull it? Empty it into a bucket?

    RE: Metric o-rings. They were metric, but they still leak. Possible i used slightly the wrong size, or PO did and I matched them. I'll check again soon.
    #11