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  1. #1

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    Question Need help with msx140 compression

    Hi guys,this is my first post.I have an 03 msx 140 with 125hours on it and i did a compression test.center cyl 80,the other two 120.i did the test right.the jet ski runs fine with a top speed of 57-58.what do you think?just go ahead and take out the head?oh forgot to say that last week i was at lake Pyramid and test it out with a yamaha fx ho and we had same acceleration and top speed. any tips would be helpfull,thanks


  2. #2
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by msx140 View Post
    Hi guys,this is my first post.
    I have an 03 MSX 140 with 125 hours on it and I did a compression test.

    center cyl 80,the other two 120.
    i did the test right. the jet ski runs fine with a top speed of 57-58.
    what do you think? just go ahead and take out the head?
    oh forgot to say that last week i was at Lake Pyramid and test it out with a Yamaha fx ho and we had same acceleration and top speed.
    any tips would be helpful, thanks
    Welcome to the Hulk!

    Low compression on the CENTER cylinder, yet you still have good speed and power?
    Was speed measured with a GPS, or the digital display?

    What RPM are you turning on the water at Wide Open Throttle?

    Have you downloaded the MSX 140 Service Manual?
    Last edited by K447; 05-18-2008 at 11:57 AM.

  3. #3

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    speed was on the digital display but i can't remember rpm.i have the manual also.

  4. #4
    ph2ocraft's Avatar
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    I'd also like to say WELCOME to the Green Hulk Forums!!
    57-58 on speedo, I think that's about 54-55 maybe even slower on the GPS.
    You should probably inspect the cylinder before you do any more riding.

  5. #5

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    msx 140 cylinder

    so guys i found the problem.what caused that deep groove?also what should be the position of the piston rings (i found that the gaps were aligned...i thought they should be on opposite sides..)
    thanks again
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  6. #6
    Click avatar for tech links/info K447's Avatar
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    Perhaps the piston ring locating pin(s) came loose?

  7. #7

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    you are right.i just so the piston.so now what?i need a new cylinder?

  8. #8

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    Contact Randy at Watcon he will have what you need

  9. #9

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    ok thanks alot ,i hope i don't need a cylinder.

  10. #10
    ph2ocraft's Avatar
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    You need to have your cylinder repaired. It can be filled and re-nik'd.
    I'd measure the fuel pressure and make sure it's within spec. I'd consider sending in the injectors and control unit to have them calibrated and make sure the injectors are spraying correctly.

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