787 Spec jetting Q's
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  1. #1
    Resident Guru DamageInc's Avatar
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    787 Spec jetting Q's

    787 w/ Spec 2
    175psi
    #5 curve
    85/88 nozzles
    46 Novi Maxflows
    135 lows
    115 mag 117.5 pto highs
    2.3n/s
    95gm
    1⅛ out on L screws
    1 mag 1⅜ pto out on highs
    Not sure what pop off is. Will check tomorrow.

    Takes a minute to get it started, not sure if pop off is too high...then r's need to be up a little before it's responsive. Once I get it to -⅜ throttle, holy **** it launches! Had a Rossier on it for years and liked the bump and reliability, but the difference between the Rossier and Spec 2 is amazing. Pulls all the way to wot. Pet tach coming. Don't know rpm #s...
    Does anyone have similar setups ? Are my settings in the right neighborhood?
    Thanks.

  2. #2
    Resident Guru DamageInc's Avatar
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    Re: 787 Spec jetting Q's

    Lotta reads, but no responses...
    Where'd all the Spec 2 gurus go...? This seems like it'd be a simple question for some of the members here.
    Good Intel from serious minded tuners is hard to come by on this site anymore. Used to be a hotbed of racers and 2 stroke heads sharing advice. Less scammers, less bs.
    Not complaining, just sayin.

    Still looking for some tuning advice if anyone is out there. Got a 720 w/44's and a Spec that I could use some jetting and water routing info on a well...
    Matt Braley is whom I'd like to reach, but haven't seen him on here in a while now.

    Anyway, just looking for a good tuners input.
    Thanks.

  3. #3
    PWCToday.com Is My Home Away From Home wmazz's Avatar
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    Re: 787 Spec jetting Q's

    Quote Originally Posted by DamageInc View Post
    Takes a minute to get it started, not sure if pop off is too high...then r's need to be up a little before it's responsive.
    What is different between your set-up with the Rossier, and the
    spec 2? Exhaust manifold, and water injection?


    Bill M.
    Horsepower == Speed, RPM != Speed



  4. #4
    Resident Guru DamageInc's Avatar
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    Re: 787 Spec jetting Q's

    With the Rossier, I had water injection and blackjacked 40i's. Punchy and reliable.
    With the Spec 2, the blackjacks didn't seem to deliver enough fuel, so I bought a set of 46 Maxflows. Ecwi is in effect as well.
    I think I have it pretty close right now. Bottom end still needs some tuning...doesn't have a hesitation from idle to 1/4, but it's not as snappy as my 750 x2 with all the bells and whistles. But once the ecwi kicks in, the pull is amazing. All the way to wot. Although I have tried dialing in the hs screw just wet, as I wanna get the low speed set first. No plug chops yet.
    Pipe has the Factory exh manifold too.

  5. #5
    Resident Guru DamageInc's Avatar
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    Re: 787 Spec jetting Q's

    Haven't* dialed in his screw yet...

  6. #6
    PWCToday.com Is My Home Away From Home wmazz's Avatar
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    Re: 787 Spec jetting Q's

    I am not an expert on this set-up. I can provide help with
    procedure and maybe some useful details.

    Quote Originally Posted by DamageInc View Post
    Takes a minute to get it started,
    Do you need to open the throttle, or can you push the button and
    start the engine without touching the throttle?

    Quote Originally Posted by DamageInc View Post
    ...then r's need to be up a little before it's responsive.
    Once I get it to -⅜ throttle, holy **** it launches!
    Quote Originally Posted by DamageInc View Post
    I think I have it pretty close right now. Bottom end still needs some tuning...doesn't have a hesitation from idle to 1/4,
    Can you do a little power tuning on the trailer?

    If no problem from idle to 1/4, where is the problem?
    Acceleration is less than a smaller carb? Is there a detail
    you are leaving out?

    Any case porting or rotary valve changes.

    The intake manifold ports were larger for the 46's?

    Which main jet booster does your carbs have?

    Are you having problems with a 5mph zone?

    Throttle response below 3/8's on Novi's should be better with their larger
    low speed by-pass holes. If you get up on the rr's, chop the throttle, and
    then grab a handfull, does it accelerate to your expectations?

    Those large holes can provide great acceleration, or cause problems.

    What is your return jet size? Do you have any other Novi accessories?



    Quote Originally Posted by DamageInc View Post
    No plug chops yet.
    A waste of time, unless you are using leaded race gas.




    Bill M.

    Are you testing on fresh or salt water?

    A Skat Trak Swirl?
    Last edited by wmazz; 07-25-2022 at 01:54 AM.
    Horsepower == Speed, RPM != Speed



  7. #7
    Resident Guru DamageInc's Avatar
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    Re: 787 Spec jetting Q's

    Only testing on fresh water.
    Return jet 60.
    No other Novi accessories.
    RV cover is a Buckshot with 46mm openings.
    No issues in the 5 mph zone.
    I do not know what main jet booster is... ?
    No RV changes or case porting.

    It runs fine. I'm mostly looking for starting points for jetting, pop off, and screw settings to gauge if I'm in the right neighborhood.
    I'll do some on trailer tuning with the pet tach on Saturday. I think idle-1/4 could be snappier.
    Thanks for your input Bill.

  8. #8
    PWCToday.com Is My Home Away From Home wmazz's Avatar
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    Re: 787 Spec jetting Q's

    Main jet booster is an automotive term for the bomb sight.

    I believe Novi has 3 or 4 different configurations. It can be used
    to assist the transition to the mains.

    Quote Originally Posted by DamageInc View Post
    I think idle-1/4 could be snappier.
    That is what I was thinking. 1/4 to 1/2 turns out. Get that circuit
    dialed in, and pull more peak rpm.


    Bill M.
    Horsepower == Speed, RPM != Speed



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