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  1. #1

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    What should i have for compression?

    First off, the ski is a 01 with 120 hrs and has a protec ride plate, intake grate, arrestor kit, prop, Turbo exhaust tube, head,clips and couplers and i checked the compression weekend and it is 115, 113, 114 with the head. I was thinking it was going to be around 150.

    Also, i purchased the ski modded and did not know to check the compression when i got it. But, it has always ran well and in the 63-65 mph range until now. The carbs are in dire need of cleaning and rebuilding(which i am doing now)

    The part that puzzles me is that i pulled the head to install the clips/couplers, i noticed that there were 2 gaskets on the bottom side of the head and 2 on the top side. So, thats 4 total head gaskets?


  2. #2
    Moderator OsideBill's Avatar
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    Post some pics of the head, the numbers sound like a stock head. did you look in the how to section at the how to do a compression check thread? 1200 OEM head gaskets are three layer gaskets, sometimes people remove the center layer to improve the squish clearance. The other one you are talking about is the head cover gasket.

  3. #3

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    osidebill,

    As far as the head, it has the stock black head cover but, has a lower silver aluminum 1-2 inch thick actual head. I was told it was a protec and a far as i can research, the silver head is not stock. Is it possible that the previous owner put the protec head on with the triple layer stock head gaskets and the stock head cover gasket?

  4. #4
    Moderator RX951's Avatar
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    the 2003/4 1200 cc heads were silver. Its possible it could have a late model head with an earlier model head cover.

    Pics will tell a lot. Shoot us a pic if you can . and yes the pro-tecs were silver.....but the compression suggest an OEM compression as Bill sed.

    and listening to the head gasket combo you have...LOL.....it could be a protec head with too many gaskets. that could account for the lower compression on a protec head....if it is a protec.

  5. #5

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    thanks guys, i wont be able to take pics until this weekend but, please stay tuned!!

  6. #6

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    Ok guys, i took some pictures of the motor. Please tell me if this is a protec head or not. Thanks again for the help!
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  7. #7
    Moderator RX951's Avatar
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    yup, thats a protec head

  8. #8

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    So why the low 113-115-112 compression? and until the carbs needed rebuilding the ski ran great. Should i pull the head and take more pictures?

  9. #9
    mrbtd's Avatar
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    Did you hold the throttle open when checking compression ? Was the battery fully charged ?

    You may be chasing a problem that doesnt exist.

  10. #10
    '02GPRider's Avatar
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    Couple things. I had a Riva-milled head that was supposed to be 150 psi and was only about 140 because I'm at 900 feet at home. The 150 rating is at sea level and you're at about 600' ASL, so it will be lower. Also, the quality of your compression gauge can really make a difference. My cheap NAPA tester reads 10 psi lower than a high quailty Snap-on tester I've compared it to. I believe this is because of where the valve is placed in the hose. In the cheap tester, the hose becomes added volume.

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