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  1. #1

    Join Date
    Apr 2006
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    Gore, New Zwaland
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    76

    Help with GP1200r offshore set-up

    Hi guys, in 2 weeks time we are doing the inaugural New Zealand Jet Ski Marathon (Horrible name), runs from the North Island to the South Island and back, about 30mile each leg. I would appreciate any input with set-up help. I have a 2005 gp1300r with the following:
    free-flow
    D-plate
    EFI at 3,5,1.5,9
    v-force and plate
    oem head re-squished and 48cc
    Riva power filter
    air/atmo sensor repositioned to near filter
    all intake holes opened out
    ductings retained but shortened
    Riva 1300 2-bar
    ppk and pump flange sealed
    Riva billet stainless housing
    modified Riva ride plate
    Dynafly 13/22
    Fuel tank baffled
    Riva trim tabs leveled
    tilted oem sponsons

    The bottom of the hull has been meticulously prepared, including long block sanding, and sharpening of all trailing edges. We test at 1000ft above seal level, last twice was with 2 foot lake chop and temp around 60degrees, water temp around 50degrees. Fuel tank is dead full, trim one up, rider weighs 220lbs, has helmet on and in seated position. We get consistent 71mph at 7180rpm, which is good but not great.

    I have just got a Jim's plate and a new ex IR dynafly 14/21 race finish. I intend to fit these before the event, but will NOT shorten the trim tabs as advised, as stability must exceed the need for speed. The ski is very stable, and gains 1mph by 3/4 tank, but by half tank gains no more as we are getting bobbling (near porpoising). I hope the better bite of the new dynafly and the different design of the ride plate (R&D) will eliminate this.

    Any help will be much appreciated, thanks, REXA.


  2. #2
    Hydrotoys's Avatar
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    REXA,
    If you have ANY rough seas...

    then install the stock rideplate, and install a 3deg 3-seater exit nozzle. You will see a dramatic drop of speed in your smooth water testing...but it will be your only hope in staying with the 3 seaters and other longer craft in the ocean. I'd not angle the sponsons. You don't want to come over the edge of the waves, only to have the sponsons send you nose down into the next wave. Neutral attitude is much faster than nose up or nose down in heavy surf. 2ft waves and ocean waves are two different conditions. If you can maintain 60-65mph in rough ocean seas, then you can win events.

    The R/D rideplates and cut rideplates have no use in an offshore event, other than to make you bounce like a rag doll. Even with the longer tabs, stock plate and 3 degree nozzle you will STILL have trouble keeping it hooked up against longer watercraft.

    If it's rough at all, or windy conditions, you will have water coming over the hood too. A strip of duct tape around the very front edge of the hood, down to the body may prevent the hood from getting ripped off at high speed. Also make sure the seat latch hole is covered with duct tape, if you are going in/out of surf area. One wierd tail landing can pop the latch and toss the seat.

    A small amount of Dielectric grease on the spark plug terminals, or any electric terminals that might get wet, will prevent arcing if the plugs and wires get wet. Careful with removing the seat, since the hinge can scoop water into the engine compartment.

    Depending on your riding preference, you may want to consider some side lifter wedges from hydroturf. Only on the outside of the footwells!!!

    I don't think I'd recommend ductbills without some type of electric bilge system. If you sit out there for any length of time, you could easily get swamped.

    Did you say 30 miles, one way? So the event-horizon is approx 24miles. Are you running with GPS?

  3. #3
    philip_gpr's Avatar
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    yes - install a 3 deg 3-seater exit nozzle (used on a FX or XLT)

    you might take the Riva plate and compare it to you stock plate, if you can get the Riva plate on the same angle (both sides and middle section) as the stock plate then you could use it

    I agree with Mark you don't need Jim's plate so you may as well send it to me

  4. #4
    ABBOTT's Avatar
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    Jul 2005
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    Birmingham, AL / Lay Lake
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    try these settings (for those mods/no porting) on your controller

    6-6-1-9 / 6-6-2-10 / and 6-6-1-10

  5. #5

    Join Date
    Apr 2006
    Location
    Gore, New Zwaland
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    I have available a 3 degree nozzle, my stock ride plate has been cut but can be shimmed back to standard. I will fit the new impellor only. Because we leave from and enter into inlets, one of which is nearly 10 mile deep, there is no surf and no horison problem. We will still do the duct taping. Sponsons will be leveled, should they be run up or down. I know that the event will not be run unless the conditions are fairly kind.
    These comments are good, need more, Thanks, REXA.

  6. #6
    philip_gpr's Avatar
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    step the OEM sponsons

  7. #7
    philip_gpr's Avatar
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    Riva trim tabs leveled

    what do you mean by this? (I use 2 washers under all 4 bolts)

  8. #8

    Join Date
    Apr 2006
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    Gore, New Zwaland
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    Phillip, by leveled I mean that they have been machined to lie perfectly parallel to the standard ride plate at the side of the plate, and also to run parallel to the hull at their leading edge. Ther was some descrepancy in their manufacture of up to 0.25mm. also why do you suggest tilted sponsons when your tabs have been lowered? Hydrotoys is saying non tilted sponsons, but does not say up or down. REXA.

  9. #9
    Hydrotoys's Avatar
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    I ran them down...I like to turn regardless of the course. With a 3deg nozzle, flat plate, and shimmed trim tabs (extended, no less) tilted sponsons will drive the nose over. I wouldn't suggest it, unless you are looking to lawn dart in at 60.

  10. #10

    Join Date
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    Check your fuel injection at sea level. You may have to adjust.

    Mark is dead on when it comes to ocean events. It is not about top speed, it is about staying on your boat in rough seas (3-8 feet). The 3 seater riders will ride their craft whereas you will be fighting with yours. Guess who's going to win?

    A steady 60 mph will win a lot of races in the ocean, but it is easier said than done. WORK OUT A LOT!

    Some Australians have reported good success with (of all things) the Shredmaster ride plate. It supposidly works well in ocean conditions. It makes sense because it is a longer plate and effectively makes the hull longer.... not to mention the stability it helps to provide. Stability is what you need to stay competative against the 3 seaters.

    A 3 degree nozzle is an absolute must! Don't waste your time with a 5 degree in the ocean.

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