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  1. #1
    GPryan's Avatar
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    2" pump extension

    What is the theory behind this piece. In other words, why was this added to the new pump?


  2. #2
    305coco's Avatar
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    they say its suppose to improve hook up i added the extension to my 02 and didnt notice any diference

  3. #3
    Moderator OsideBill's Avatar
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    It was added in 03 when the GPR went from 1200 to 1300 the new HO pump was not released until 05. It helped with hook up

  4. #4
    cheatin' piston popper addicted's Avatar
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    I'll take a stab at the theory. 1, it gives the water more room to be compacted before entering the prop, thereby increasing hookup.

    2, it changes the relationship between the converging wake at the rear of the ski, the thrust angle, and the actual distance behind the ski that the high pressure water is actually pushing against the stationary water. somehow that adds speed when done right. My Polaris uses a 4" extension from the factory. the yamaha is 2" and I think the rxp's is something just short of 2".

  5. #5
    All hail the Chief! fullboogie's Avatar
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    Quote Originally Posted by 305coco View Post
    they say its suppose to improve hook up i added the extension to my 02 and didnt notice any diference
    Me neither.

  6. #6
    RUNWME's Avatar
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    Quote Originally Posted by addicted View Post
    I'll take a stab at the theory. 1, it gives the water more room to be compacted before entering the prop, thereby increasing hookup.

    2, it changes the relationship between the converging wake at the rear of the ski, the thrust angle, and the actual distance behind the ski that the high pressure water is actually pushing against the stationary water. somehow that adds speed when done right. My Polaris uses a 4" extension from the factory. the yamaha is 2" and I think the rxp's is something just short of 2".
    what he said

  7. #7
    Happily Self-Employed WFO's Avatar
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    Questions:

    (1) How many GPR1200s have you ever heard of with a broken crank ?

    (2) How many GPR1300EFIs or 1300BB w/carbs and 2" extension have you ever heard about with broken cranks ?

    Answers:

    (1) A whole bunch
    (2) Never heard of one

  8. #8
    vomitspot's Avatar
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    i was told by skattrak set back pumps allow the impeller to have more water available = improve hook up

  9. #9
    GPryan's Avatar
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    Thanks for clearing that up. Makes a whole lot of sence to me.

  10. #10
    All hail the Chief! fullboogie's Avatar
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    Quote Originally Posted by WFO View Post
    Questions:

    (1) How many GPR1200s have you ever heard of with a broken crank ?

    (2) How many GPR1300EFIs or 1300BB w/carbs and 2" extension have you ever heard about with broken cranks ?

    Answers:

    (1) A whole bunch
    (2) Never heard of one
    What's the connection? How is a pump extension preventing crank failures? Need info dude - definitely a good reason for this mod, but it's not why I did it.

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