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  1. #1

    New to the sport and have an issue with a 99 GP800X

    Hi guys,

    My cousin came over with her/my uncle's 99 GP800X. Her and her boyfriend launched it and she rode it over to our dock. It apparently was not running correctly and she said it just wouldn't rev up all the way and was idling rough.

    I am a four stroke quad guy, and thought that I could take a look at it in case it was something easy so they didn't have to take it in. My cousin said it had run like this before and that there friend told them to run a hotter plug. so they swapped the plugs and it seemingly ran better.

    I was pretty certain they had not been maintaining the bike so my first idea was to look at whatever air cleaner setup to check for any restrictions/etc. As you guys already know that there is not much of an air cleaner/filter on them so that was probably not it.

    Next I checked the plugs and they were a day old and very oily. My thoughts now are that there might be a fuel filter clog that is not allowing the proper mix.

    Anyway I am new to these toys and thought I would run it by you guys for thoughts and troubleshooting ideas. I will now start searching


  2. #2
    Also, It is bone stock and they have been running it on regular (89oct) fuel and yamalube 2 stroke oil.

    I wonder what the compression ratio is on these motors and if premium fuel is would be better. I run all of our quads on premium.

  3. #3
    If your not doing something, its hard to screw up. stlouisramsfan's Avatar
    Join Date
    Jul 2007
    Pontoon Beach Illinois
    Is this a gp800r? someone will lead this in the right direction....

  4. #4

  5. #5
    crashhard's Avatar
    Join Date
    Jul 2007
    Philly PA, Wildwood NJ, Indialantic FL
    fuel filter, carbs then cdi. thats usually my run down. But I include fuel lines when I do the fuel filter.

    how many hours on the ski?

  6. #6
    jdog800's Avatar
    Join Date
    Feb 2007
    Alexandria L.A.
    This is a powervalve 2 cylinder ski. Try opening the powervalves all the way by hand (unplug the pvmotor) and roll the powervalves till they are open, and see if its better on topend. This is going to be a dog out the hole but it will be a good starting test to see if possibley your powervalves are not opening all the way.

  7. #7
    ? How does that work? Do you have any pictures or diagrams? 2 strokes and I don't really understand each other that well.


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