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  1. #1
    carbuff91's Avatar
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    Triple Pipes and props?????

    Ok,

    Here's the thing... 2001 GP1200R triple pipe boat...stock pump with a 13/20 setback...RPM's 7850 and 74mph. So, install new 05 pump with 14/20 Dynafly...now RPM's about 7500 and speed 74mph....what gives??? What type of pitch would be needed to gain back the lost RPM? Is it possible to even loose that much through just a pump swap with the possible wrong pitch on the prop???

    Please help...MUDBUG is coming!!!!

    Thanks,
    Steve


  2. #2
    xyzyx00's Avatar
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    what are your other mods?

  3. #3
    carbuff91's Avatar
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    Basically a Riva Stage III kit

  4. #4
    xyzyx00's Avatar
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    the steeper prop will lose some rpms but you should see some improvement - theres gotta be some other guys running a similar setup that can shed some light on the subject? sounds like something else is wrong somewhere... i dunno

  5. #5
    philip_gpr's Avatar
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    what nozzle are you using? 85 mmm or 87 MM

    Solas impellers are never the pitch they say they are

  6. #6
    GPR114's Avatar
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    Don't think youve got time but I know a ski with that setup and similar results. Had to bend it to a 13/19 to get it to pull and picked up a couple mph. Factory pipes on 1200s like 7700 to 7800 rpm. Call Carl @Island. Hope this helps! You may be able to depitch that prop without remachining. I don't know.

  7. #7
    Moderator Insanediego Joe's Avatar
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    gpr 114 got it right. You need to depitch that 14/20 to a 13/19 and your rpms and speed will be perfect.

    FYI, dont run your gpr at 7500 rpms.That puts you into a world of detonation and engine damage. You want no less than 7700 rpms when running the pipes.

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