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  1. #1

    gp1200r has no power, need help diagnosing the problem

    i have an 02' gpr and when i run it, it only goes about 27mph (or 4000 rpm) i took it all apart and replaced the crank seals and installed a new piston cause the old one was blown, and it still only runs about 27mph i looked else where and from what other people have posted i might need a carb rebuild,
    also if this helps with diagnosing the problem, the blown piston had scrapes/scratches running down it (vertically) the cylinder wall appears to be in good condition

    could this rpm problem be electrical or do i need a new top end?? i did have the stater replaced about 6 months ago and i have gotten new spark plugs for it.

    could you tell me the possible reasons for this happening?

    it has been ridden in salt water

  2. #2
    correct me if im wrong, but i looked up what happens to a 2 stroke when you dont mix oil in the gas and the guy showed the piston and it looked exactly like the own that was blown, so i guess this means carb rebuild time

  3. #3
    Compression test would be the first step

    Is your premix or injected?

  4. #4
    injected and ill test them right now

  5. #5
    well i went out to check the compression and i go to start it and water spews out of the pistons >=( im done with this machine, and on top of that the new piston has 0 compression, im no newb at this stuff but it really pisses me off to know that the head gaskets or the base gaskets are installed wrong and theres also probably a bunch of water in the crank im justr going to sell this peice of crap

  6. #6
    On top of that theres saltwater im the crank :'( its ruined for good

  7. #7
    silver93t's Avatar
    Join Date
    Jun 2012
    Don't give up so easily. First get all the water out of the motor. Then take a break from the ski and take some time to do your research. These skis are relatively easy and cheap to fix. For an easy fix you could always pick up a rebuilt shortblock for $1000-1500 depending on what you go with. If you were only hitting 27 mph, there is a good chance you were running on 2 cylinders. How did the plugs look? Signs of combustion on each one? Scrapes on the piston mean either you had a lubrication problem, or a ring broke or the motor ingested something.The carbs should definitely be gone through.

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