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  1. #1
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    Timing diffs between 750 and 780

    Anyone know the difference in the timing curves on the 750 to 780 cdi? We threw the 780 Cdi in the SLT when I swapped the 750 into the PSI ski the one day for testing and my buddy burnt a piston while putting around. The ski was running alittle lean. Just wondering if htere's a big diff.


  2. #2
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    Any thoughts?

  3. #3
    100 MILES OF HEAVEN AND I AM SMACK IN THE MIDDLE KEYZBUM's Avatar
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    Quote Originally Posted by Keddano View Post
    Anyone know the difference in the timing curves on the 750 to 780 cdi? We threw the 780 Cdi in the SLT when I swapped the 750 into the PSI ski the one day for testing and my buddy burnt a piston while putting around. The ski was running alittle lean. Just wondering if htere's a big diff.
    my gut says,,,Thats not why you turned that piston into a whistle
    if you bent a rod or shattered the piston ,maybe too much adv. in the timing .
    but from what i remember the 780 is only tiny bit better(move adv) than the 750 ,,,unlike the 785 is way more ...
    And this wasent sombodys friend Cris was it ????cuase then we know it was just him
    mattman

  4. #4
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    It just smoked a hole thru the top. On 2 strokes,from what I've been told, right were the torque and HP crosses on the chart,is the hottest piston will get. Which is normally just before it really builds rpm's,basiclyy about mid throttle.He was just tooling around at I guessing about 4200 rpms steady throttle. Then OUCH. I've never even have looked at the wash pattern on that ski because it always ran good at stock carb settings all summer long,I you can imagine the hell I out it thru last year. Wide open 10 mile runs up the river,Playing Spray tag with Sterling.
    I would like to run the 780 cdi for a few more R's,and the wire is cut on it.
    Guess I'll just richen the carbs and go from there if the timing isn't to much steeper.

  5. #5
    Moderator beerdart's Avatar
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    750 24 deg @ 3000rpm Early models 16-25 deg depending on year.
    780 24- 28 deg @ 3000rpm depending on year
    1997 785 32 deg @ 3000rpm
    1998-2000 785 36 deg @ 3000rpm

  6. #6
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    Thanks Steve,Is 3000 rpm where MAX Advance is reached?

  7. #7
    Moderator beerdart's Avatar
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    Yes..

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