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  1. #11
    PWCToday.com Is My Home Away From Home
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    Re: Dual SBN 46 tuning

    What do your plugs look like?

    Im not much on kawi jetting either but the Jet works 900r with dual 46 black jacks im runing is 120 pilot and 130 main with 27 psi pop off. Starts and idles like a stock sj and i dont have to ride around bliping the throttle to keep it cleared out. When I pull the trigger it goes.

    reverse jetting does give a very little better hit out of the hole but most setups will load up if you dont keep it cleared out. If your racing every little bit counts, im not a racing.

    when I received the carbs from jet works they were reverse jetted.

  2. #12
    Resident Guru JC-SuperJet's Avatar
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    Re: Dual SBN 46 tuning

    A bone Stock 2009 SuperJet might do 44mph at best. A bone stock JS750sx/sxi would hit 48mph+. Not good if your Limited/Mod 750 SX is slower...

    For reference, my pump gas 2012 SuperJet with DASA PV 850cc Stock Stroke w Dual Mikuni 46mm Carbs and Factory B Mod Pipe plus Stock Ignition w MSD Enhancer has:

    135 Pilot Jet

    130 Main Jet

    2.5 N/S x 115gr Spring = 19psi Pop-Off

    She runs 55mph+

    What is your Compression? Ported Cylinders usually require higher Compression to make up for the loss of Trapped Compression if the Exhaust Ports were made taller.

    I would do Pop-Off tests on both carbs to verify that the Needle Valves are not leaking before pop-off. Any fizzing or bubbling before pop is a leaking Needle Valve. Replace NV O-Ring and re-test. If it is still leaking, install brand new Needle Valves as the Needle may be worn. Leaking Needle Valves will cause a rich bottom condition and bog the Engine down.

    Also, since the Carbs seem hard to tune-in, suggest you do an Air Leak-down test on the Engine. Maybe there's an Air Leak around your Intake Manifold since you recently swapped Carbs, and maybe the Crank Seals are leaking.
    Last edited by JC-SuperJet; 09-07-2018 at 11:52 AM.

  3. #13
    Resident Guru JC-SuperJet's Avatar
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    Re: Dual SBN 46 tuning


  4. #14
    Top Dog
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    Re: Dual SBN 46 tuning

    Quote Originally Posted by JC-SuperJet View Post

    For reference, my pump gas 2012 SuperJet with DASA PV 850cc Stock Stroke w Dual Mikuni 46mm Carbs and Factory B Mod Pipe plus Stock Ignition w MSD Enhancer has:

    135 Pilot Jet

    130 Main Jet

    2.5 N/S x 115gr Spring = 19psi Pop-Off

    She runs 55mph+
    That seems really slow for an 850.. What impeller are you running? my 701 single 46 61x SN with all of the mods and 9/15 hooker does 49mph.
    triceps are the biceps of the back of your arm.

  5. #15
    PWCToday Regular
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    Re: Dual SBN 46 tuning

    Quote Originally Posted by JC-SuperJet View Post
    A bone Stock 2009 SuperJet might do 44mph at best. A bone stock JS750sx/sxi would hit 48mph+. Not good if your Limited/Mod 750 SX is slower...

    For reference, my pump gas 2012 SuperJet with DASA PV 850cc Stock Stroke w Dual Mikuni 46mm Carbs and Factory B Mod Pipe plus Stock Ignition w MSD Enhancer has:

    135 Pilot Jet

    130 Main Jet

    2.5 N/S x 115gr Spring = 19psi Pop-Off

    She runs 55mph+

    What is your Compression? Ported Cylinders usually require higher Compression to make up for the loss of Trapped Compression if the Exhaust Ports were made taller.

    I would do Pop-Off tests on both carbs to verify that the Needle Valves are not leaking before pop-off. Any fizzing or bubbling before pop is a leaking Needle Valve. Replace NV O-Ring and re-test. If it is still leaking, install brand new Needle Valves as the Needle may be worn. Leaking Needle Valves will cause a rich bottom condition and bog the Engine down.

    Also, since the Carbs seem hard to tune-in, suggest you do an Air Leak-down test on the Engine. Maybe there's an Air Leak around your Intake Manifold since you recently swapped Carbs, and maybe the Crank Seals are leaking.
    Compression is 185
    Itís gotta be a carb or a pipe issue
    The powerband is just weak
    Carbs are spigot mounted
    Maybe need new ones if it is letting in air
    Motor was just rebuilt so crank seals should be out of the equation
    Needle valve is gonna be next step
    Maybe a new head pipe as mine is the old style 2 screw and I might be losing power from the pipe not being tuned right.



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