Js300/300sx rev limiter removal?? How to gain more rpm??
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  1. #1
    PWCToday Newbie 1994kawasaki750xi's Avatar
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    Js300/300sx rev limiter removal?? How to gain more rpm??

    Hey guys, I want to increase the rpm on the 300, was wondering if anyone has any info on how to possibly do this?? Or realistic remove the rev-limeter?


    I heard of the non rev spark cdi box but hoping there is a easier way or something I could replace it with??
    Any info or any leads on how to do this?
    Thanks.


    All thatís done:


    High compression head (180psi)
    Bn38 carburetor
    Boyesen Double flap reeds.
    Reed stuffer.
    Port and polished
    Lighten fly wheel. (.8lb removed)
    Kerker pipe
    Aluminum water box
    Westcoast Flame arrestor
    Skat trak 13/16 impeller
    Ported pump
    Reduction nozzle bored (testing a few sizes)
    Fresh Wiseco piston .5mm over
    New crank bearings/seals.3E43C95E-898D-461C-A963-260ECFDD8ED8.png

  2. #2
    PWCToday.com Is My Home Away From Home wmazz's Avatar
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    Re: Js300/300sx rev limiter removal?? How to gain more rpm??

    No RPM, ZERO.

    Rpm limiters do not restrict peak rpm. Instead they prevent
    problems like your connecting rod splitting into 2 pieces, or
    the crank webs from breaking.


    Bill M.

    A reverse jetted 34 or 38sbn, or a 38sbn-i from a SeaDoo
    720 reverse jetted. And access to a machine shop.

    A custom dry pipe.

    Watercraft pipes inject water to prevent the rubber coupler
    from melting, and to prevent the pipe from heating the engine
    compartment and reduce HP.

    Because of the water injection, and how the pump and impeller
    apply a rpm limiting force on the engine, only a few hundred rpm
    is possible.

    It is the opposite of a car or motorcycle where the load on the engine
    decreases after acceleration. The Jet Ski requires Full Power to maintain
    peak rpm, and only substantial gains in peak HP will increase speed by
    a few mph.
    Last edited by wmazz; 07-23-2022 at 01:08 AM.
    Horsepower == Speed, RPM != Speed



  3. #3
    PWCToday Newbie 1994kawasaki750xi's Avatar
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    Re: Js300/300sx rev limiter removal?? How to gain more rpm??

    This is what I’m looking for you can read in the picture I posted this is from the 300 post in the Facebook group. The 300s used to have something like that and I’m just hoping to get more RPM which the CDI controls I believe so I’m just trying to find anything I can switch it with or something like that.

    My ski is running good and everything just seems like it tops out and could use some more RPM, motor sounds really good and quiet and it’s moving pretty fast.
    Just looking for idea’s!!


    A71B1884-43FC-41A3-B798-45F172F7C6D3.png

  4. #4
    PWCToday.com Is My Home Away From Home
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    Re: Js300/300sx rev limiter removal?? How to gain more rpm??

    Unless you are hitting the rev limiter; having a cdi with a higher rev limit is not going to do anything for you. If you are hitting the rev limit on the cdi you need to increase the pitch of your impeller. To increase rpms, your best bet is to dry out the exhaust as much as you can before things start to melt.

  5. #5
    PWCToday.com Is My Home Away From Home
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    Re: Js300/300sx rev limiter removal?? How to gain more rpm??

    Lots of good info here as well for building up the 300 engine:
    https://www.x-h2o.com/threads/melmac...x-build.89656/

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