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  1. #1
    DanSVHO's Avatar
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    Valve/keeper problem?

    Wondering if anyone has had a 18+ svho bend a valve because of factory keeper/valve component failure. My cyl three was ruined because of this. Melted piston rings to piston
    and lost compression. Tech is saying it is because of poor machining
    from factory but Iíve never heard of this before. Ski barely has 20 hours.


  2. #2

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    DanSVHO I am sorry to hear of your problem with your ski, does your SVHO have any Mods done to it or is it factory stock.

    Obviously # 3 is dead, but what is the compression on the others 1,2,4 ? Problem isolated just to # 3 only?

    You have been having problems with this 1.8 for some time now.

    C J

  3. #3
    sound more like a lean condition that stuck ur valve and piston. stock or mod ski.

  4. #4

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    A melted piston is caused by a combination things, of being too lean, and detonating. A bent valve, intake valve not seating, bad valve seat leaking air into cylinder, too much timing, intake gasket sucking unmetered air, clogged injector ,too small injector, vacuum leak.
    Last edited by cjk6119; 11-26-2019 at 02:55 PM.

  5. #5
    DanSVHO's Avatar
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    To clarify, all other cylinders, 1,2,4 had good compression. Th ski is not stock however it’s not modded anywhere near my old svho. I had retainers installed, unfortunately not by me, and I’m fearful that the installer is to blame. It ran fin for some time but then developed a heavy sputter as If a coil was unplugged in that cyl. Dealer verified it was a scorched piston/rings-and said that on that cylinder, the keeper, valve and retainer where all damaged on exhaust side only. I don’t think that’s a coincidence and leads me to believe whomever installed the retainers did not take the time to do it correctly.
    Quote Originally Posted by cjk6119 View Post
    DanSVHO I am sorry to hear of your problem with your ski, does your SVHO have any Mods done to it or is it factory stock.

    Obviously # 3 is dead, but what is the compression on the others 1,2,4 ? Problem isolated just to # 3 only?

    You have been having problems with this 1.8 for some time now.

    C J

  6. #6
    DanSVHO's Avatar
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    I installed retainers with the intention to do the same mods as my last ski....eventually. More so for the Safety factor. So I could run a bit higher rpmís without worry. I still have the stock wheel and all stock fuel components except for the fuel pump all the other mods are simple bolt ons including, Fizzle, ribbon removed, intake, prop, wedge, and tune.

  7. #7

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    So DanSVHO, What are your options at this point? Do you have an idea on what you want to do?
    What does Yamaha have to say or is this where you got your diagnoses?
    I hope the outcome is good for you with regards to your ski.

    Hope you and your family have a great Thanksgiving.

    PS It looks like the exhaust was back feeding into the cylinder #3 byway of its exhaust valve not being totally seated on the valve seat. No back pressure on #3 exhaust either and a lot of exhaust was entering #3 instead of exiting the the exhaust manifold and going out to the waterbox.

    Cj
    Last edited by cjk6119; 11-26-2019 at 07:50 PM.

  8. #8
    Quote Originally Posted by DanSVHO View Post
    Wondering if anyone has had a 18+ svho bend a valve because of factory keeper/valve component failure. My cyl three was ruined because of this. Melted piston rings to piston
    and lost compression. Tech is saying it is because of poor machining
    from factory but I’ve never heard of this before. Ski barely has 20 hours.
    if the ski is under warranty and the tech is saying it's because of poor machining from factory let them fix it. if the valve is bent from hitting the piston then it drop a valve. did the keepers come out.
    Last edited by yellow jacket; 11-26-2019 at 10:21 PM.

  9. #9
    outnumbered's Avatar
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    Sent you a PM

  10. #10
    DanSVHO's Avatar
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    cj, thanks for the kind words. The ski is fixed already. I ended up getting a new short block from Yamaha. The purpose of the thread was to get feed back from those who may have experienced the same thing. I am trying to understand how and or why it happened in the first place so that it doesn’t happen again. Also, I’m interested to hear opinions on what the tech told me. From what I gather, The only way piston rings would melt to a piston causing loss of compression completely in that cylinder would be if the exhaust valve was stuck closed and not letting the gases escape causing extreme heat resulting in the piston rings fusing to the piston.
    Quote Originally Posted by cjk6119 View Post
    So DanSVHO, What are your options at this point? Do you have an idea on what you want to do?
    What does Yamaha have to say or is this where you got your diagnoses?
    I hope the outcome is good for you with regards to your ski.

    Hope you and your family have a great Thanksgiving.

    PS It looks like the exhaust was back feeding into the cylinder #3 byway of its exhaust valve not being totally seated on the valve seat. No back pressure on #3 exhaust either and a lot of exhaust was entering #3 instead of exiting the the exhaust manifold and going out to the waterbox.

    Cj

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