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  1. #1

    Gp1200r Power valve dropped into the piston

    alright fellas, had the 2001 gp1200r out the other day and it was running strong and then wouldnt go above 45mph. The third cylinder wasnt firing so we pulled the ski and ran a compression test. 95 in the front 110 in the middle and 0 in the back. Today i pulled the head and found that i had a nice chunk missing from the side of my piston and that the power valve is weged inside the exaust port. What causes this? I know im gonna need a new piston and im looking for a used third cylinder with power valve if anybody has one. Is there anything else i should be looking for. The head looks clean no nicks. Here are some pictures for reference.

  2. #2
    Moderator RX951's Avatar
    Join Date
    Apr 2005
    League City, Texas
    This is oh so common. You need to repair the damage, and install waveeater clips. This is a must do modification to help bulletproof the PV's from dropping again. It prevents the pin from sliding out and the valve dropping.
    PV clips

  3. #3
    but it wont help if the bolt shears off like one I have did.
    This is only after 30 hrs.

  4. #4

  5. #5
    All hail the Chief! fullboogie's Avatar
    Join Date
    Nov 2005
    Lots and lots and lots and lots of information on this under the search button.

  6. #6
    gaz1's Avatar
    Join Date
    Jan 2008
    Yeah,i agree with the search button,waveeater clips are a must but there is so much i would be doing with that engine,giving it a good clean and a lick of paint for a start.Search gpr/xlt accel pump removal thread and that airbox would also be gone,as well as that coupler on no.2 if it drops into the case.

  7. #7

    Join Date
    Aug 2007
    Bridgeton nj
    yamahaman, is your ski stock, like carbs, intake, cylinders and oil injection, how did it run before it blew, if your running injection pump what oil are you using? my 1200pv blew last year, wrist pin bearing let go, it had 200hrs and the carbs needed to be rebuilt, I rebuilt with sleeve 1300pv cylinders, cleaned and re jetted carbs. put 50hr on it, runs great and now Im always checking my plugs for carb tuning. check and see if you PV really hit the piston because when I had my stock ski apart I couldn't get the power valve to hit the piston, there is a stop before it hits, now I know when you get them ported they widen the exhaust port and grind into the stops witch allows the PV to hit the pistons and alot of tuners just pin up the PV,

  8. #8
    pokechop2006's Avatar
    Join Date
    Jun 2009
    summerville sc
    so my girls ski has 75 hours stock,should i worry?

  9. #9
    the bolt that holds the clip that holds the pin for the power valve sheared off like 96Waveventure700's did. The ski is completely stock with the exception of a D-plate. The carbs were rebuilt 30 hours before this happened and up until then the ski ran great. hit 60-63mph no problem. Right now its sittin at 348 hours.

  10. #10

    Join Date
    Aug 2007
    Bridgeton nj
    You 348hr on that top end piston and rings? what oil you running and is it premix or oil injection? put a straight edge along the cylinder and let me know if the PV will hit it? thanks Paul

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