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  1. #1

    Gp1200r carb rebuild low pop off HELP!

    Hi so I have followed bills jetting specs for the gp1200r. But I'm getting pop off at 35-37 psi.
    jets are 110 and 125main spring is 95g. The spring arm is level with the carb body.

    How can I get the pop off up? Bills specs say between 42-43 from memory?


  2. #2
    Also it's soked with wd40 and opened the needle and seat manually to get it down the hole

  3. #3

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    Bill told me the newer springs from Mikuni vary quite a bit. He said to stretch the spring to get the number you want. Get it to 40 lbs and you will be ok. The important thing is that they all be within a lb or 2. Don't stretch it too much, it doesn't take too much to get it.

  4. #4
    Okay thanks I have another question...
    Once full of wd40, and the spring stretched. I get the first pop off at 47 psi then the pressure drops to about 40 psi and holds, if I continue to pump after the first pop off of 47 the next 3 or 4 pops are 42psi. If I fill it with wd40 again and start again it's the same. 47 first pop then keep pumping and it pops every time at 42 psi.

    so do you go by the first pop or the pops after the first pop?

  5. #5

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    I always count the first pop as my reading. I use a pressure regulator to supply the air, and slowly increase the pressure until it pops off. the thing is after it pops the first time you no longer have a good amount of WD40 to seal it the same.

  6. #6

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    If you stretch the spring too much, just compress it completely with your fingers a few times and it will go the other way.

  7. #7

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    Are you absolutely sure that your pressure gauge is completely accurate? It could have been regestering 35-37 but the actual pressure could be closer to 42-43. Mine typically regesters 40-41 psig.

    I blame the descrepency on the gauge.

  8. +1 by:

    WFO

  9. #8

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    ^ I agree. I was worried when mine was reading 39-40 but after they were all the same I just blamed the guage..

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