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  1. #1
    o uncola o's Avatar
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    Milling stock head.

    Anyone ever put one of the motors on a dyno after milling the OEM head to see what (if any) power gains there were?


  2. #2
    Nope but your ass will tell you there's a big increase.

  3. #3
    vomitspot's Avatar
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    there are very few watercraft dynos
    the norm is raised compression will gain bottom end/acceleration on a 2 stroke

  4. #4
    o uncola o's Avatar
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    Quote Originally Posted by VOODOO View Post
    Nope but your ass will tell you there's a big increase.
    I hate relying on the "seat of the pants" dyno... but, if it is really that different, I will probably do that mod during this off season.

    Anyone know why the Solas web site lists the 14/20 as the proper impeller for the GP1300R (05-07) on their site if that prop is too big for the stock motor to spin... just wondering...

  5. #5
    WAVEATER WAVEATER's Avatar
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    i installed that impeller with a few mods in place but it was to much prop for my motor, doggy out of the hole and through mid range. sent my stock head down to JIm and he milled it for what was probably the most bang for the buck of any of my mods and she really came alive. Jim's Performance set me up right. just remember to shim your exhaust mounts to compinsate for the shaved head. Oh yea, Jims plate added about 4 mph to my top end too!

  6. #6
    gordon lasiter #328's Avatar
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    milled head

    if you mill the heads you want to have a fuel controller installed.....make sure to not take off to much at a time......

  7. #7
    I know that when you shave the head the ski will "feel" much lighter. Also, with the head shaved you can turn the 14/20 dynafly so it has to be giving you a lot more torque.

  8. #8
    A milled head is about the easiest "engine mod" you can do without getting into expensive time consuming mods. The difference in hp yield with a milled head vs a aftermarket head will be nominal at best, if you want a little more power polish that head once its milled. Its usually the first thing I do when I start messing with my motor, becareful if the motor has a ton of hours becasue higher compression is more stress then a motor is use to.

  9. #9
    txgp1300r's Avatar
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    45 thou sqish is a good starting point. I took off .010 at a time till I hit my mark of .045 squish...my cranking compression with starter motor turning engine 400 rpm is 140 lbs. mid grade fuel friendly

  10. #10
    o uncola o's Avatar
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    So you can run 89 octane at 140 lbs?

    Quote Originally Posted by txgp1300r View Post
    45 thou sqish is a good starting point. I took off .010 at a time till I hit my mark of .045 squish...my cranking compression with starter motor turning engine 400 rpm is 140 lbs. mid grade fuel friendly

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