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  1. #1

    Posting piston, jug and pv pics after pv failure - please opine

    My son bought a 1999 Yammy XL1200 with 105 hours on the meter, used in fresh water. The ski is currently apart in my garage (I am Dad & Chief Mechanic).

    He ran the ski an hour or two and routinely hit approximately 60 mph - I think he clocked it via GPS.
    The ski was a little doggy out of the hole with 1 person aboard. He reported that the engine red lined immediately when throttle was pulled, thus we suspect cavitation. We will deal with that issue later.

    The PO reported that the carbs were rebuilt 1-2 years ago due to use of ethanol spiked gas. I am dubious that the PO reported accurately or completely about previous problems since there is significant liquid grunge inside the hull. The trim cables were frozen when we got the ski, we have a scoured impeller housing and an impeller that is pitted on its leading edges, and the general look of the ski says little attention was paid to its preservation/maintenance. However, all systems look to be connected and look original. The cat look like new - no clogging and no broken bits.

    The more immediate problem is that on review of the ski we found a slipped pin on the #1 power valve.
    Pics of the PV, the #1 jug & piston, and the other two jugs are attached. Before dis-assembly we tested compression cold, 1 plug out at a time, wide open throttle. Got essentially 100-100-100#s.

    How do you folks feel about the following repair plan for the engine only - I will deal with carbs and lube options later. We want a reasonably reliable "stock performing" ski for towing tubes, boards and easy going slalom skiers.

    replace #1 piston;
    replace all 3 sets of piston rings;
    hone jugs only to break any glaze;
    split crank case and flush crank & bearings in mineral spirits;
    replace 1 stock PV;
    add PV keepers;
    reassemble with new gaskets & crank seals.

    Thanks for your thoughts.Click image for larger version. 

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    Last edited by TW - Twisted Wrench; 06-04-2012 at 09:34 PM. Reason: typo


  2. #2
    Pics of #1 PV compared to #2 PV, & metal specs below:
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  3. #3
    mudslanger's Avatar
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    Replace all the rings and the bad power valve do not hone the cylinder use it as is. the piston looks good in the pics. as far as i can see. and use the wave eater clips not the couplers.

    If it were my ski i would be replacing everything because the power valve would fall all the way into the cylinder and kill everything.

    this is the 3rd cylinder ive seen this week like this.

    Good luck with the build.

  4. #4
    Happily Self-Employed WFO's Avatar
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    replace #1 piston;
    replace all 3 sets of piston rings;
    hone jugs only to break any glaze;
    split crank case and flush crank & bearings in mineral spirits;
    replace 1 stock PV;
    add PV keepers;
    reassemble with new gaskets & crank seals.
    thats the way I would do it

  5. #5
    Thanks for the advice guys.

  6. #6
    Happily Self-Employed WFO's Avatar
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    I do like to upgrade the pv linkage couplers to something other than stock on a rebuild... the stockers can get very worn and sloppy

  7. #7
    Who should I go to for upgraded couplers? OsideBill?

    Thanks again

  8. #8
    redneck71's Avatar
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    I got mine here along with the clips did everything at one time http://www.waveeaterproducts.com/

  9. #9

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    I'd do rings and light hone. On a side note, judging by the (lack of) piston wash it looks like it was running lean.

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