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  1. #1

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    97 GP 1200 Help Needed.

    Hi everyone.

    Having a issue with my 97 GP1200 and need some help.
    It has the famous low end bog at pull away. It happens and won't go above 2500rpm unless I feather the throttle for around 10 seconds then it takes off like a rocket.

    Recently purchased it and I had the carbs open and there was seized screws in each carb so I could not go further.
    I'm also not sure when last it was rebuilt. But all the diaphragms look ok.

    I have tried tuning it with a gunson colortune spark plug. (A clear spark plug that let's one see the color of the combustion inside the cylinder). I have found that cylinder 1 has a nice complete orange glow.
    And cylinders 2 and 3 have like a now-and-then orange explosion much less than cylinder 1. Until I get it over the "low end bog" when it takes off then the 2 and 3 glow orange like cylinder 1.

    I know its not spark related because I can clearly see the spark but no combustion.

    Engine appears to be stock and I'm not sure of the jetting. But I know that it has a silver spring on the needle valves.
    I have also replaced the manifold and carb gaskets to no avail.

    Just for info, ski was on the trailer but in the water when it was tested.

    Any ideas on what I could try?


    Many Thanks!


  2. #2
    Happily Self-Employed WFO's Avatar
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    sounds like you need to open them low speed screws some to adjust your low end problem

  3. #3
    yz450f's Avatar
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    I have always tested my skis in the water as if I was going to use it for the day. Sometimes if I ran it too long in the trailer at the ramp it would stir up all sand and mud and end up running through my engine and that's no good! Try it in open water next time. Good luck

  4. #4

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    When I turn the low screws it does nothing to the color and consistancy of the combustion.
    Its like its not Getting enough fuel. But I cleaned the carbs the best I could and all the pulse lines are secure.

    Also, the water it was running in had no sand or mud in it. And I kept an eye on the water filter and the water coming out the side. So That's all good.

    Compression is also good. 1:105 2 and 3: 120

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