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  1. #21
    PWCToday.com Is My Home Away From Home wmazz's Avatar
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    Re: Impeller Direction Pitch Down or Up for More Top Speed Based on Peak HP

    Quote Originally Posted by beerdart View Post
    20:1 thats a lot of oil any problems fouling plugs.
    Quote Originally Posted by zpilot View Post
    Not sure on the 20:1 Bill recommended, sounds like a break in ratio to me.
    Back in the 80's, factory Yamaha's Ricky Johnson's father wrote an article in one of
    the MX mags about the benefits of using 20:1 oil mixtures. Since then I have found
    other articles and shops that run 20:1. Benifits are increased ring seal, less friction,
    wear, and the possibility of a few extra HP.

    It works great. Especially when you begin the tuning process. It won't prevent a
    major seizure, but ime, it does prevent small seizures that are common to forged
    pistons.


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



  2. #22
    Resident Guru zpilot's Avatar
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    Re: Impeller Direction Pitch Down or Up for More Top Speed Based on Peak HP

    [QUOTE=wmazz;4465257]The process is similar to setting pilot screws on a car, but a water craft needs to be under
    a load. Specifically, a low idle. I prefer ~1000 rpm. The idle should be low enough to hold
    your hand behind the pump. If a smooth low idle isn't possible the first time, adjust it twice.

    Are you familiar with the difference between low speed and pilot screws. Carburated street
    bikes have pilot screws (most of them have no access unless you remove the plug that
    covers them).

    Not sure, but is the pilot the idle setting screw that adjusts the butterfly? I usually set this to barely keep idle then use low speed to adjust to feel the changes and bring it up to good idle. With my current setting I definitely need to size up on the jet to get close to 1/2-1 turn.

    PJS main seals are red colored on the metal side. Kawasaki are green colored on the metal side
    of the seal.

    If you have the red main seals, they are the worst of the worst. I read about the supposed
    horror stories about ethanol affecting main seal and chuckle, but PJS seals are the real deal.
    Ethanol will melt, soften them until there is nearly no seal left.

    If you have these red colored seals, it is important that you take care of them because leaking
    main seals will affect the carburation. Especially the pilot screw settings that can rob you of
    peak rpm.

    Kawasaki reed cages have a rubber layer near the tip of the reeds, but PJS reeds have no
    rubber on the ends of the reed cages. We used to be concerned about premature wear
    to the PJS reeds.

    Mostly I was concerned that you may be loosing peak HP, if you replaced the PJS reeds with
    Boyesen dual stage reeds.


    No idea on the seals or reeds. I haven't touched them.


    Isn't your head gasket copper? If it is, it can be reused many times so long as it is annealed.

    PJS heads were machined with less clearances between the head studs and stud holes, and
    that makes a PJS head more difficult to remove when compared to a Kawasaki head.


    Yes, copper gasket, with white sealant.
    Last edited by zpilot; 02-21-2018 at 01:29 PM.





    1995 Kawasaki SC

    PJS Viper 9000 800cc
    PJS Exhaust Manifold
    Coffmans Full Exhaust
    Custom Jetinetics Flywheel/drilled ring gear
    12 Vein SS Magnum Pump
    10/18 Skat Track Swirl Impeller
    PJS Rip Turn
    DG Intake Grate






    1994 Kawasaki XIR
    Group K Head Mod
    PJS Exhaust
    Skat 9/17 Big Hub Swirl
    UMI Bars

  3. #23
    Top Dog bandit88's Avatar
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    Re: Impeller Direction Pitch Down or Up for More Top Speed Based on Peak HP

    Here are the specs for one of my Viper 9000 cylinders, It did have some light port work done to it, but exhaust port height and duration are stock, it was just widened a tad.

    specs.jpg
    -95 750SXI
    -86 440 with PJS800 conversion - http://www.pwctoday.com/showthread.php?t=466927
    -90 TS650
    -91 300SX

  4. #24
    Top Dog bandit88's Avatar
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    Re: Impeller Direction Pitch Down or Up for More Top Speed Based on Peak HP

    Quote Originally Posted by bandit88 View Post
    Here are the specs for one of my Viper 9000 cylinders, It did have some light port work done to it, but exhaust port height and duration are stock, it was just widened a tad.

    specs.jpg
    With that, Top deck to top of the exhaust was ~38.8mm and exhaust port height, top to bottom, was ~32.5mm
    -95 750SXI
    -86 440 with PJS800 conversion - http://www.pwctoday.com/showthread.php?t=466927
    -90 TS650
    -91 300SX

  5. #25
    Resident Guru zpilot's Avatar
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    Re: Impeller Direction Pitch Down or Up for More Top Speed Based on Peak HP

    Bandit, you are the man. Thank you for the info.





    1995 Kawasaki SC

    PJS Viper 9000 800cc
    PJS Exhaust Manifold
    Coffmans Full Exhaust
    Custom Jetinetics Flywheel/drilled ring gear
    12 Vein SS Magnum Pump
    10/18 Skat Track Swirl Impeller
    PJS Rip Turn
    DG Intake Grate






    1994 Kawasaki XIR
    Group K Head Mod
    PJS Exhaust
    Skat 9/17 Big Hub Swirl
    UMI Bars

  6. #26
    Top Dog bandit88's Avatar
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    Re: Impeller Direction Pitch Down or Up for More Top Speed Based on Peak HP

    Quote Originally Posted by zpilot View Post
    Regarding port timing, I spoke with John Newsom from Jetski Haven years ago and he said the following. (Only info I have)

    "I do know the port timing and all in that engine will not let it run much over 6500 rpm's. The engine has most of its power on the bottom and mid range. To transfer some of that power from the mid to the top you will have to raise the port timing. That is what we discovered when we started building these engines with the Kaw 750 base (Case & Crank) it raised the port timing up 2mm."
    I would delete any info you have from John out of your brain. I bought my first 800 cylinder from him. Was supposed to be a complete motor in good shape. Had to ride him hard to ship the thing out months after I payed for it, was about to file a paypal claim. Got the motor and most of it was junk, stroker crank, vilder flywheel, cases, all junk. Luckily the the parts I cared about most, cylinder and head were untouched and usable. Also ordered Wiseco pistons from him, and he sent me WSM. Glad it turned out that way since I dont like forged pistons, but he still owes me the difference in price. I have seen a few videos of his builds, the guy is a hack. Rant over lol.
    -95 750SXI
    -86 440 with PJS800 conversion - http://www.pwctoday.com/showthread.php?t=466927
    -90 TS650
    -91 300SX

  7. #27
    Resident Guru zpilot's Avatar
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    Re: Impeller Direction Pitch Down or Up for More Top Speed Based on Peak HP

    Yes, I've heard others say they had issues with him before. Info I got from him was about 10 years ago and was just conversation, didn't buy anything. I purchased 2 of out 3 viper motors from Gordy as New old stock including the one currently in the ski. Your spec sheet and the feedback everyone on this thread is providing is very valuable and info I've been after for a very long time.





    1995 Kawasaki SC

    PJS Viper 9000 800cc
    PJS Exhaust Manifold
    Coffmans Full Exhaust
    Custom Jetinetics Flywheel/drilled ring gear
    12 Vein SS Magnum Pump
    10/18 Skat Track Swirl Impeller
    PJS Rip Turn
    DG Intake Grate






    1994 Kawasaki XIR
    Group K Head Mod
    PJS Exhaust
    Skat 9/17 Big Hub Swirl
    UMI Bars

  8. #28
    Top Dog bandit88's Avatar
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    Re: Impeller Direction Pitch Down or Up for More Top Speed Based on Peak HP

    Nice that you got them from Gordy. Did he have the original pistons and everything for them back then? What ignition are you running? I would think that the 10/18 would be pretty close to where you want to be. Maybe a tad tall but nothing that should be holding you to 6500 rpm
    -95 750SXI
    -86 440 with PJS800 conversion - http://www.pwctoday.com/showthread.php?t=466927
    -90 TS650
    -91 300SX

  9. #29
    Resident Guru zpilot's Avatar
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    Re: Impeller Direction Pitch Down or Up for More Top Speed Based on Peak HP

    They were all complete assembled Viper 9000HT motors with the Ebox mounted above the flywheel cover. Basically Viper crank case with a Kawasaki 650 crank, Kawasaki 550 nose, 550 flywheel with a larger ring gear and 550 electronics. I'm pretty sure it does not have the rev limiter some Kawasaki 550's had. They were assembled by PJS back in the 90's. You can see the attached article on the second page the ski it was built for.

    The 10/18 is really good overall and I could definitely live with it but I've gotten the itch to see if I can fine tune and get more out of it.
    Last edited by zpilot; 02-21-2018 at 04:44 PM.





    1995 Kawasaki SC

    PJS Viper 9000 800cc
    PJS Exhaust Manifold
    Coffmans Full Exhaust
    Custom Jetinetics Flywheel/drilled ring gear
    12 Vein SS Magnum Pump
    10/18 Skat Track Swirl Impeller
    PJS Rip Turn
    DG Intake Grate






    1994 Kawasaki XIR
    Group K Head Mod
    PJS Exhaust
    Skat 9/17 Big Hub Swirl
    UMI Bars

  10. #30
    Top Dog bandit88's Avatar
    Join Date
    May 2014
    Location
    Green Bay WI
    Age
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    Re: Impeller Direction Pitch Down or Up for More Top Speed Based on Peak HP

    Oh you have the full setup, sweet! All other running ones Ive seen are just the top end on a 650 bottom. I wonder if the old 550 coil is just breaking up at higher RPM? Maybe see if it will rev higher out of the water.
    Last edited by bandit88; 02-21-2018 at 04:48 PM.
    -95 750SXI
    -86 440 with PJS800 conversion - http://www.pwctoday.com/showthread.php?t=466927
    -90 TS650
    -91 300SX

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