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  1. #1
    skywalker
    Join Date
    Aug 2007
    Location
    kansas
    Posts
    11

    2001 GP1200R limited power "intermitant"

    I built this motor out of random decent parts off of other 1200's, just so you know that up front. From a dead stop sometimes it will take off like it should and hit about 7500 rpms, other times it flat lines at 5000 rpms. Used to be if you hopped the ski a little, it would then take off, wierd. The ski is bone stock. Issue happens cold or hot, runs awesome when it isn't acting up. Sometimes it will run great on and off the gas for a couple min., then it will act up again.

    Things I have changed or done allready:

    - Compression is around 110 on all cylinders
    - plugs have been changed
    - fuel trap door removed
    - converter changed (due to the one in it had broken loose)
    - waterboxed changed, found some debrit from old converter in it
    - carbs were taken appart and checked prior to reassembly( still not out of the ? yet)
    - main fuel filter clean
    - cdi box changed

    I am unsure on how the sensor right after the converter works. I plug it in and the ski runs like crap, i unplug it and it still runs like crap. The old converter wipe bent the sensor for the converter that was on it when I first tested it. Thn I put on a converter system(brand new), but I dont know what year it is. Im thinkn the old sensor was busted and wasnt working right, and the new one doesnt match the cdi, am i thinking wrong? Superramjet has the bypass chip I am going to try tomorrow. I haven't ruled out the stator, and I have one anothor one of those. When it starts running bad I can pull the wires off one at a time, and all they all seem to still be running. So I am 95% positive there isnt a miss, just limited power.

    Hope someone can help me, or might know about this problem

    Thanks


  2. #2
    skywalker
    Join Date
    Aug 2007
    Location
    kansas
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    11
    I am sure I fixed it, the problem was low compression. I removed 2 of the head gaskets plates to raise the low compression, and it ran fine. I then installed new pistons, I will try it tomorrow. Thanks for all the help

  3. #3
    Hydrotoys's Avatar
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    Jul 2005
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    Mesa, AZ
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    Welcome to the board SW.

    If I were to guess, with what info you have there, I'd say something is intermittent in your power valve system. Bad motor, water in connector, sloppy linkage, backwards cable, etc....

    Try this.
    Disconnect your PV's in the closed position. Your launches should be consistant. Manually open them. Your launches should suck, but be the same.

  4. #4
    Mongoose's Avatar
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    Aug 2005
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    Wales
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    Something intermittent like this could be down to something like a dodgy fuel flap in your tank-They are known to cause issues. Do away with it to eliminate that from your list.

  5. #5
    Moderator RX951's Avatar
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    Apr 2005
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    welcome to the forum skywalker

  6. #6
    mrbtd's Avatar
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    Jul 2005
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    If you were getting small amounts of water in the cylinders this would happen. Have a look @ the plugs.

  7. #7
    skywalker
    Join Date
    Aug 2007
    Location
    kansas
    Posts
    11
    Its fixed, the problem was low compression. I was using a crappy gage to test. I installed new pistons and left the single head gasket. The compression is 130 even now across all the cylinders. The thing hit 62 mph, I was impressed. (wouldnt think compession would cause an intermitant loss of power, but it does. My only thought is that the carbs were not getting the correct, strong, pulse they needed.)

    Later guys

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