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  1. #1
    Banned User
    Join Date
    Apr 2007

    Wink Everyone input please 03' - '07 GP1300R's

    I'd like to know the best thing I can do to increase top speed on my 2004 GP1300R w/ Riva stage 2 and forum ideas done.
    __________________________________________________ ____

    This is a complete breakdown of my crafts set-up:

    * Riva rideplate (grinded about 1/4" off of mounting surface to hull, plus one large washer under the front most of craft position for increased angle.Had enough for clearance for stepping from shoe to plate yet. No dragging.)
    * OEM trim tabs (one large washer under front most of craft postion)
    * R & D reed stuffers
    * Riva Compression head kit
    * Free flow exhaust
    * 87mm exit nozzle
    * Power filter
    * E.F.I. controller
    * 13/19 SB concord impeller (repitched to 14/21SB)
    * Pump plug kit
    * Top End loader grate (was thinking of trying an OEM grate, but after reading about the horror stories on doing this will not do it now!)
    * Stepped OEM sponsons (front of craft most up and back of sponson most down position.)
    * Filled pump shoe holes
    * Dumping Cylinder #3 water overboard
    * Romoved shipion tube to reduction nozzle
    * cut bottom of storage bin off and lifted hood with 1 large washer under each bold under mounting bracket
    * Put extra washers under the mounting bolts on the rideplate to fill up the gab a little bit
    * Removed the windscreen on both sides under hood / body panneling
    * Run 93 octane all the time
    * Lost 15 pounds since last year
    * Boat does have scratch marks of regular wear and tear under the hull though. (problem, or can I do something about it to increase top end speed?)
    __________________________________________________ _____

    2004 GP1300R Custom Riva stage 2
    HP: unknown (please input your thoughts)
    RPM: dial indicating 7,250 or better (don't have a rpm reader)
    MPH: 70.4
    Operator weight: 228

    I would like the input from anyone that knows something else that I can do or buy (within a reasonable budget) on my 2004 GP1300R.

    Thanks for your help

  2. #2
    JetSkiDaddy's Avatar
    Join Date
    May 2005
    Houston, TX
    05 Pump with Dynafly prop
    Fercho VF3 Reeds
    Jims FF plate

  3. #3
    Join Date
    Feb 2007
    Cape Town, South Africa
    was that speed taken with a gps ?

    What i dont understand with your choices (mods) you have some goodies for bottom end (holeshot) and other goodies for speed. its erractic, you need to decide whats inportant, holeshot or top speed.

    If you want speed do the following:

    Your impeller is totally wrong: (concord design)
    You either need a solas dynafly (setback or not) or a skattrack Swirl type R

    use the stock 85mm nozzle (87 is for holeshot).

    plug the visibility spout/ pisser. (you can just clamp the pipe or install a block off nut.)

    You have an 04, youll need to either get your pump blueprinted or buy the new HO pump (05+ spec)

    Re-install the stock water box, free flow is for holeshot,

    Remove the OEM trim tabs.

    The reed stuffer is kind of pointless, rather get vforce 3 reeds.

    Get either Jims FF plate or the Island Racing stage 4 plate.

    Remove the rear grab handle (the big black thing on the back of the seat), thats saves about 14 pounds

    You have free speed here:

    Reinstall stock waterbox
    Reinstall 85mm nozzle
    remove the OEM trimtabs
    plug the visibility spout
    remove the grab handle

    youll be amazed !

    thatll give you allot more top end, at the expense of holeshot. (You cant have it both ways).

    Safety wise you need to do the following:
    Wave eater clips and couplers (for your powervalves)
    Carbon fibre pump tunnel re-inforcement

    Also check your rpm;s (get a tiny tac asap !), thats the only way to set your efi correctly.
    Last edited by spaceman; 05-20-2007 at 12:43 PM.

  4. #4
    Banned User
    Join Date
    Apr 2007

    reply to last posting

    It's my personal opinion not to subtract from my holeshot. If that means not getting my top end up to what I'm looking for, then that's the way it's going to have to be. I don't see how taking off the handle is going to do anything. It shaves 14lbs maybe ya, but how do you get back on the waverunner after your exhausted? Also, I don't see how plugging up the "pisser" is going to help any, I think it's just they thought of water pressure being wasted. I don't see that much of a difference in doing that. Keeping the free flow exhaust may cause some speed loss, sure. But I don't want the possibility of dedonation occuring inside the engine. (This is worth my while to keep it on. If my engine has problems, the top end that I could of got without the free flow on won't matter at that point.)
    I'd like to go with a modded ride plate, but if you call Jim and talk to him, he'll tell you right out that you will lose certain handling abilities of the craft if you do so. That don't make me excited??
    Again, if I remove a part (such as OEM trim tabs ) you'll lose that handling ability with the craft (that don't make me excited either.)

    I do say that the idea of blueprinting my pump or going with an '05 set-up is a good idea. Also, the V force 3 reed idea is good too.
    I did fail to mention that I do have the WaveEater couplers and clips installed. If the 14/21 Set Back impelller isn't correct, then at what RPM would I think about changing the pitch to a higher one? Also, is 7,250+ (on my digital tach.) to much for that impeller?

  5. #5
    KamikazeGPR's Avatar
    Join Date
    Mar 2007
    I have jims original j-plate on my stock 06.It went from a baseline of 65.9-66.3 to 69.7-70.2. At the time i installed the plate, I also installed the 1200 grate,ppk,r&d tabs and filled the holes.A pickup of 4mph,but it could be more.The tabs and grate dont help speed.

    The ski stays perfectly planted and straight at WOT. Alittle looser in turns,but i dont know anyone taking turns at 70+.

    Since you already have the efi controller and heads.Your best bet is the 05-06 pump with the dynafly($524)1.5-2mph and the vf3's($500)no direct mph gain,but that extra 100 rpm may get you up to a 14/22 dynafly and jims ff plate($400)easily 4-5 mph.Keep the stock tabs and sponsons.You should be @ 75 with that if set-up right.

    The 800 grate will give another 1mph,but youll lose some holeshot with it.

    I have all these parts sitting on the bench, it kills me not to be able to use them right now due to lack of 93 fuel on the river. I'd love to be jamming a 75 mph ski.

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