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  1. #1

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    1997 GP1200, 57.5 on gps. Too slow!

    Had some really good water today and got some good top speed runs in. The best I could do with my completely stock ski (it has aluminum trim tabs from George) was this:



    After taking my 100% stock, 2013 VXR to 67.5 on gps, this GP1200 needs some more top speed. I hear that a nozzle from a 98 GP1200 is a good first step. I'm going to have to find one. I'm going to have to study the modification sticky, too.
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  2. #2
    Myself's Avatar
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    I Believe the '99 exhaust stinger or 1100 stinger works better too.

  3. #3

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    Quote Originally Posted by Myself View Post
    I Believe the '99 exhaust stinger or 1100 stinger works better too.
    Okay, thank you. I'll keep that in mind. This ski has good power off the line and through the midrange but the '97s just don't have much top end. I'd like to fix that .

  4. #4

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    I was hoping that the sticky at the top of the page, "97-99 GP (65u) mods" would have some good information to help me make this ski faster. Unfortunately, the linked page in the thread is dead.

    The weather is starting to warm up so hopefully this forum will start to get busy. I know there are some forum members with much faster GP1200s. Any and all replies/advice is much appreciated.

  5. #5
    Myself's Avatar
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    You should update the carb jetting and do the balanced return mod.....just for reliability. you could also buy a new head gasket and drill out the rivets on it, then remove 1 or 2 layers before installing. That will bump your compression a bit. Or if you really want to, you could get the head milled and squish band corrected. The squish is actually set up horribly wrong on these heads in stock form.

  6. #6

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    Check your pump out too. Is it the stock impeller?

    Doesn't matter if you spend loads on the engine, you won't get good speed with a worn out pump

  7. #7

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    Quote Originally Posted by Raider1200 View Post
    Check your pump out too. Is it the stock impeller?

    Doesn't matter if you spend loads on the engine, you won't get good speed with a worn out pump
    Pump seems to be in good shape. No cavitation and the ski pulls reaaaaaal hard from a standing start. I've never suspected anything wrong with the pump or the stock impeller. That being said, I haven't taken any feeler gauge clearance measurements either.

    My brother bought the ski new in 1997 and I got it from him 8 or 9 yrs ago. It's been well cared for.

  8. #8

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    Quote Originally Posted by Myself View Post
    You should update the carb jetting and do the balanced return mod.....just for reliability. you could also buy a new head gasket and drill out the rivets on it, then remove 1 or 2 layers before installing. That will bump your compression a bit. Or if you really want to, you could get the head milled and squish band corrected. The squish is actually set up horribly wrong on these heads in stock form.
    I've been into the carbs about once a year for cleaning due to crap ethanol gas. The jetting is completely stock as it came from the factory.

    Will jetting get me any additional power? I'm still using the OEM airbox.

    What is the balanced return mod?

    The engine is running 100% perfectly! Lots of punch and never complains at WOT!

  9. #9
    Quote Originally Posted by dannyual777 View Post
    I've been into the carbs about once a year for cleaning due to crap ethanol gas. The jetting is completely stock as it came from the factory.

    Will jetting get me any additional power? I'm still using the OEM airbox.

    What is the balanced return mod?

    The engine is running 100% perfectly! Lots of punch and never complains at WOT!

    You shouldnt jet carbs unless you increase or decrease air flow in or out other wise you will run too rich

  10. #10
    Myself's Avatar
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    If the engine runs perfectly, just keep doin what your doin. I don't have my notebook handy but the jetting change on an otherwise stock machine was to make all 3 pilot jets the same and bump them up a bit. Many of these "65u" engines experience an off idle hesitation. It takes care of that. Also this setup is known for creating so much pressure on the fuel system that the pump check valves crease. This results in loss of fuel pressure and lean running. The balanced return mod drills the restrictions out of the carb return passages and uses a jet in the return line to balance pressure as a whole system and prevent pressure spikes on individual carbs and the resulting creased check valves.

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