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  1. #1

    GP1200 no compression in middle cylinder!

    Hi guys,
    just bought this 2000 GP1200 and it has only 70 hrs with lots of mods in it, took it out to the lake, it ran great for about 15 mins and it started bogging and wouldn't go more than 40 mph. Took it home, did compression test and got 115 psi on cylinder 1 and 3 but 0 on the middle. Took the head off and here's what I found. Any suggestions? Much appreciated!
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  2. #2
    Is that a shadow or is it missing a chunk of the piston?

  3. #3
    Moocher of Skis The River Skank's Avatar
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    deff missing a chunk. I bought a used jug and piston off ebay threw it on and 2 years later ski is still running great. Other wise send the jug off and get a new piston if you wana go new.

  4. #4
    It is missing a chunk! Any ideas how it happened?

  5. #5
    Moocher of Skis The River Skank's Avatar
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    It happens. Cylinder probably ran lean. Its a good idea to have the carbs gone through as well.

  6. #6
    Moocher of Skis The River Skank's Avatar
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    What kind of engine mods are you running? Do you have the higher compression head?

  7. #7
    elmatta's Avatar
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    It's on the valve side so I am guessing it smacked the valve. Push the piston down and look at the valve from the side and take pics. Is it missing a chunk? I dont see wave eaters

  8. #8
    Here are some more pics!Click image for larger version. 

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  9. #9
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    Last edited by Alpacino; 08-04-2013 at 12:31 AM.

  10. #10
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    Last edited by Alpacino; 08-04-2013 at 12:31 AM.

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