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  1. #1

    Join Date
    Jun 2011
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    hopewell,Va.
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    gpr lean runaway

    i have an 00 gp1200r that i have owned for about two yrs. now and in that time i have worked over the carbs installed the d=plate and sensor chip, installed the riva 1200 intake grate and ride plate sealed the pump shoe twice,installed new piston rings, all new gaskets and the ski has run pretty good all summer. i have noticed recently that i might be experiencing what some guys here call a lean runaway. the engine only does it at cold/first start=up and the engine will rev up on its own to about 5k rpms but after about 30sec it will calm down to its normal rpms when on the hose. it does not rev up when i flush the motor after a day of riding nor does it do it while i am riding or after a short rest. i am wondering if my engine has a small leak in the crank case or something. i did a cyl leak test early on in the season but the engine would not hold the 10lbs of pressure but it would hold 5lbs with a 1lb loss after 6mins. i was thinking that maybe i did not have really good seal on the engine. has anyone had a similar situation with their gpr. any input is appreciated.


  2. #2
    THE PLATE MAN JIM'S PERFORMANCE's Avatar
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    Nov 2005
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    Quote Originally Posted by rich.allen View Post
    i have an 00 gp1200r that i have owned for about two yrs. now and in that time i have worked over the carbs installed the d=plate and sensor chip, installed the riva 1200 intake grate and ride plate sealed the pump shoe twice,installed new piston rings, all new gaskets and the ski has run pretty good all summer. i have noticed recently that i might be experiencing what some guys here call a lean runaway. the engine only does it at cold/first start=up and the engine will rev up on its own to about 5k rpms but after about 30sec it will calm down to its normal rpms when on the hose. it does not rev up when i flush the motor after a day of riding nor does it do it while i am riding or after a short rest. i am wondering if my engine has a small leak in the crank case or something. i did a cyl leak test early on in the season but the engine would not hold the 10lbs of pressure but it would hold 5lbs with a 1lb loss after 6mins. i was thinking that maybe i did not have really good seal on the engine. has anyone had a similar situation with their gpr. any input is appreciated.
    carbs. are to lean fatten it up a bit.

  3. #3

    Join Date
    Jun 2011
    Location
    hopewell,Va.
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    139
    i turned the low speed screw out a 1/4 turn today on #3 carb since that is the cyl. running leaner than the other two. i have read elswhere on this forum that the 1200's are notorious for #3 cyl running lean. i did the drilled return\restrictor mod on the carbs but condition remains. makes me think there might be an internal leak. bottom half of the motor has never been gone through.

  4. #4

    Join Date
    Jun 2011
    Location
    hopewell,Va.
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    139
    wanted to add some more info today, i started the engine today after sitting for a week and this time i used my primer set up with the disabled accel pump to see if adding some more fuel at start up would cure the runaway. when firing up,the engine sounded alittle loaded up but quickley cleared out and started to rev up to about 5k. so while it was reving up i pulled back on the choke and the engine calmed down. it will also calm down on its own . i pulled the #3 spark plug wire while it was running and did not notice any difference in the way the engine ran. i can pull the #2 spark plug wire and i can hear a difference in the engine so i know #2 is firing. if i pull #1 spark plug wire the engine will not stay running and will die out. i checked the spark on #3 and it is good and i know it is getting fuel because the spark plug is wet.

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