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  1. #1
    There is no VooDoo like BadVooDoo NeVerMind's Avatar
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    Builders...Carbon Build up UNDER piston?

    I am tearing down my rec ski due to water and I cam across something I have never seen before. On piston 1 and 2, on the back side of the piston top (near where the rod and piston meet) is a buildup of black carbon, like something was burnt there.. Any ideas on what that might be from? Anyone else see something like that?


  2. #2
    PolarisNut's Avatar
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    Quote Originally Posted by NeVerMind View Post
    I am tearing down my rec ski due to water and I cam across something I have never seen before. On piston 1 and 2, on the back side of the piston top (near where the rod and piston meet) is a buildup of black carbon, like something was burnt there.. Any ideas on what that might be from? Anyone else see something like that?
    It's burned oil. Happens when the mix is a little lean, and the dome runs hot. Whats the wash look like on the top of the piston?

  3. #3
    WATER WOODY's Avatar
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    Quote Originally Posted by PolarisNut View Post
    It's burned oil. Happens when the mix is a little lean, and the dome runs hot. Whats the wash look like on the top of the piston?
    +1 the motor has run hot from a lean condition. Pics of the piston wash will tell alot.

  4. #4
    All hail the Chief! fullboogie's Avatar
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    Is it burned, or is there a caramel color? Dummies above are correct, however.

  5. #5
    There is no VooDoo like BadVooDoo NeVerMind's Avatar
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    It's not just carmel, it's a full on layer of burned up oil I guess.. (I can scrape it off)

    Can't really speak to the piston top color because of the wash and wax it got (previous owner put base gasket in wrong) The original problem was loss of oil and blown 3rd piston. that was fixed, but it looks like the other 2 pistons were not replaced. I know because 1 and 2 are oem, 3 is an SBT piston.

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