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  1. #1
    icky002's Avatar
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    What midrange on gp1200r?

    The 01 Gp1200r I have runs good, but I have a hard time going between 25-40 miles an hour. I can go slow and the exhaust is really loud and making all sorts of pops and groans. Then, even feathering the throttle, when I get to a certain piont WHOOSH, ski snaps forward and goes right to 60+ mph? I figure it's the powervalves opening, but dang, if I have a passenger they almost get thrown off.

    Is this normal or should I have a better transition to midrange and the ability to go 35 mph if I wan? Carb problem maybe?

    127 hours. D-plate, wavereaters. I rebuilt carbs over the winter (first time ever doing anything mechanical) so maybe therein lies the problem. Thanks my Yamaha brothas.


  2. #2
    Gus13letter's Avatar
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    So this occured just after you rebuilt the carbs? Sounds like maybe the pop off pressure may be set too high. Did you replace the springs? You may want to check that and try a different spring. Either that or something may be sticking, like needle and seat.

  3. #3
    icky002's Avatar
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    Well, I only rode the ski one time before I rebuilt the carbs. I didn't change any new springs or anything, just replaced the rubber seals. So a carb issue you think, or maybe a powervalve servo problem? I dunno. I am gooing to send carbs off to someone who knows what they are doing.

  4. #4
    icky002's Avatar
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    Just bought a powevalve servo off a board member. Thought I would try that first since it's easy to get too and after doing some searching seems like it may help.

  5. #5
    nunnink23's Avatar
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    reviving an old thread because i have the same issue and its really annoying, i have a completly fresh motor and reeds and carbs, all working perfectly so i doubt its a carburation issue, i never noticed this harsh powerband before because my motor used to load up so bad because the reeds were SHOT that i couldnt notice the powervalves opening. so did you end up fixing it? or is there another fix for it?

    ps: my cables are adjusted TIGHT just like yamahas service manual wants, and i ordered wave eater couplers to take up slack and see if that helps.

  6. #6
    All hail the Chief! fullboogie's Avatar
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    Assuming carbs (i.e. popoff) are correct, it is normal to have a sudden increase in power when the PV's open. If it's very dramatic, you may want to look at PV cables and adjustments.

  7. #7
    nunnink23's Avatar
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    Quote Originally Posted by fullboogie View Post
    Assuming carbs (i.e. popoff) are correct, it is normal to have a sudden increase in power when the PV's open. If it's very dramatic, you may want to look at PV cables and adjustments.
    its VERY dramatic, makes it un rideable in chop with 2 people above 4k rpm because it just hits and your going 55 and you try to back off and it falls down to 4 again. the cables are adjusted to be pretty tight, yamaha wants .06" max slack which basically is no slack so thats how i have them and i tried less slack which made it worse.

    ps: pop off is stock, i cant check it because my gauge only goes to 60psi and its supposed to be 82 psi, but the needles dont leak so its in the ball park of 82 without a doubt.

  8. #8
    icky002's Avatar
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    for me it ended up being the powervalve servo motor wasn't working, and the powervalves were stuck open all the time. Are your powervalves cycling after you turn your ski off?

  9. #9
    nunnink23's Avatar
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    yea they are, its working just fine, but its just rediculously sharp still

  10. #10
    icky002's Avatar
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    Take a look at this post from OsideBill: http://greenhulk.net/forums/showthread.php?t=70129

    Your popoff seems way too high.

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