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  1. #1

    2005 12f any history of timing chain problems?

    Hi , I am new to this forum I just picked up a 05 12f mechanics special ski is in awsome shape except for the blown engine . Just got it apart today 3 cracked pistons +all the exhaust valves bent. I havent checked the bottom end yet but already thinking rebuilt long block might be easyer than fixing this one (1800 from sbt) just started pricing everything out thats what brought me here. Any info about this engine and possible timing problems would help because i think thats why all the exhaust valves slammed into the pistons?

  2. #2
    Show some pics of the broken pistons.
    All 3 pistons broke because slammed into exhaust valves? If so, that's very unusal.

  3. #3
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    Quote Originally Posted by meangreenman View Post
    Show some pics of the broken pistons.
    All 3 pistons broke because slammed into exhaust valves? If so, that's very unusal.

  4. #4
    upon further inspection you are correct the exhaust valves did not cause this damage. detonation possibly? sorry the pics are a little blury but you can see on the intake side of the piston pieces are cracked off exposing th top ring.

  5. #5
    Just like I expected... broken off by the intake valve pocket on the piston. That's a typical detonation problem on 12'Fs high compression pistons. If the head is not damage, it may be cheaper to just replace broken pistons. Make sure keep the engine running cool and use high octane fuel now on if this will get fixed.

  6. #6
    thanks for the quick reply , correct me if im wrong but it looks like all the intake valves bent due to detonation not hitting the pistons ? when i checked the timing before
    disesembly it looked like the timing was right on although i did find the spring missing from the timing chain adjustment screw? its funny how ithe manual reads 87 octane is ok.
    with 11.5 to 1 compression that should be a no brainer

  7. #7
    12F has the highest compression among Kawi pwc engines, 235+ psi. Yet, the piston is extremly light or should I say very flimsy!

  8. #8
    That happened to a friends 12f also. Kawi replaced pistons and swapped to an updated ecu. That was under warranty but it might be worth calling a dealer to see if they can do something for you.

  9. #9
    Pain is fear leaving your body.... rlovebk's Avatar
    Join Date
    Aug 2008
    So. Cal.
    Ummm, This looks familiar. Same thing happened to my ski. 72 hours later now still running strong.
    The MeanGreenMan would know more about this than me. But I do know my ecu was changed.

  10. #10
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
    Join Date
    May 2008
    I thought the issue was with 2003 and 2004 skis not the newer ones, guess I was wrong


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