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  1. #1

    Join Date
    Apr 2010

    Rebuilt GP1200R Performance - a little lacking?

    I have just purchased a broken 2001 GP1200R and rebuilt it - it was in a bad way. It needed new crank, pistons, cylinders etc.

    It has about 10 Hours on the engine now (still using mineral 2 stroke oil atm) and I have done a number of WOT runs however the numbers don't stack up.

    According to my trusty tiny tach, max RPM are 7250 - according to my GPS max speed is 57.8MPH in neutral trim. This all seems a bit low - even for a stocker. Compression is 115psi all cylinders.
    I think it is running a touch rich although I have already made it a little leaner.

    It has a few after market bits and pieces on it as well.
    - Worx intake grate
    - Solas prop (not sure of the pitch though
    - R&D billet coupler
    - Freeflow exhaust kit
    - Jetworks exhaust mod
    - Exhaust D plate mod
    - Wave eater clips for the PVs
    - carbon tach reeds
    - Riva reed stuffers
    - R&D pro flow arrestor
    - carb accelerator pumpr removed
    - chokes removed and primer installed.
    - premix only - oil injector pump removed.

    Are these numbers reasonable?

    Regards, Mal...

  2. #2
    philip_gpr's Avatar
    Join Date
    Dec 2005
    yes, motor is fine

    7250 is perfect, I wouldn't be going leaner without checking pistonwash and/or plug chops at WOT

    the following 2 parts are slowing you down

    Worx intake grate

    Freeflow exhaust kit

    a nujet 6.0 or 6.5 will be 2 mph faster than the Solas 13/19 you arecurrently using

    I trust you have changed your carb jetting to something like 110, 120, 1.5 N/S

    try 2 washers under all 8 trim tab bolts and then grind some material off the rear rideplate mounts

  3. #3

    Join Date
    Apr 2010
    Thanks Philip.
    I will check those couple of things.
    So raise the Trim tab about 40thou however I am not sure where you are referring to with this?
    "try 2 washers under all 8 trim tab bolts and then grind some material off the rear rideplate mounts"

    Yes, carb settings altered to 110, 125, and 1.5 n/s.

    I might get rid of the FF kit as I am not sure I need it. The ski is LOUD and it had an annoying resonance between 3.5K-5K rpm.
    regards, Mal.

  4. #4
    wAVe juMpiN fOOl
    Join Date
    Jul 2010
    what exactly do u grind on ride plate????

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