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  1. #1
    dduck dduck1628's Avatar
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    Riva open loop plate, porpoising now

    I finally got to run my ski in some smooth water today. Riva Grate, closed loop cooling w/heat exchanger and did some grinding/sanding to fit the intake grate so that it would sit flush with the rideplate. Now I'm porpoising like crazy. It reminds me of my GPR. I have the potential to go faster just need to keep the front in the water. Does fine until I hit 75mph and the slightest ripple sends me bounching. Now if I stay seated my weight will keep it stable, but as soon as I lift my weight off the seat it starts bouncing. I know I can run faster than before because in seated position with my weight toward to front I can run equal to my previous best with the stock plate in full out race position standing near the rear. The way I see it I can shim the plate to bring the rear down a little or buy the Riva blockoffs than extend the hull or maybe both. I currently run OPAS removal plates. What do you guys think?? Anyone with experience with this?


    BTW attached are images of the grate fitting change before and after.
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  2. #2
    Moderator beerdart's Avatar
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    Sponsons.. I am a GPR guy can you adjust the sponsons? Angle plate=Angle sponsons.

  3. #3
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    How much fuel did you have in it when it did? When you installe the grate, did you remove ALL the previous silicone?

  4. #4
    dduck dduck1628's Avatar
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    Quote Originally Posted by beerdart View Post
    Sponsons.. I am a GPR guy can you adjust the sponsons? Angle plate=Angle sponsons.
    I used to own a GP1300R, LOL. Angling those sponsons was the 1st thing to hit my mind. LOL Wish I could adjust them, running stock sponsons...Now shimming the rear of the plate, well most of us X GPR guys know all about that lol. Just never tried it on the RXP.

  5. #5
    Whats that whistling noise? jtskier11's Avatar
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    Quote Originally Posted by dduck1628 View Post
    I finally got to run my ski in some smooth water today. Riva Grate, closed loop cooling w/heat exchanger and did some grinding/sanding to fit the intake grate so that it would sit flush with the rideplate. Now I'm porpoising like crazy. It reminds me of my GPR. I have the potential to go faster just need to keep the front in the water. Does fine until I hit 75mph and the slightest ripple sends me bounching. Now if I stay seated my weight will keep it stable, but as soon as I lift my weight off the seat it starts bouncing. I know I can run faster than before because in seated position with my weight toward to front I can run equal to my previous best with the stock plate in full out race position standing near the rear. The way I see it I can shim the plate to bring the rear down a little or buy the Riva blockoffs than extend the hull or maybe both. I currently run OPAS removal plates. What do you guys think?? Anyone with experience with this?


    BTW attached are images of the grate fitting change before and after.
    If you dont have RE's. Now would probably be the time to get some.

  6. #6
    dduck dduck1628's Avatar
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    Quote Originally Posted by Danny View Post
    How much fuel did you have in it when it did? When you installe the grate, did you remove ALL the previous silicone?

    Danny I started out with somewhere between 1/2 and 3/4 tank of fuel. Ran it down to slightly above 1/4. I cleaned every bit of RTV off the grate and hull. I pulled the grate on and off I'll bet 30 times while fitting it. I removed material from the mounting surface at the rear of the grate a little bit at a time to get it to sit flush with the rideplate. Before I did this I didn't get the opportunity to run on smooth water, but it seem like it was porpoising then.
    I played with the trim as well. Trimming down helped but it would still bounce. If I stayed in the seated position until I was above 78mph. I could slowly lift my weight off the seat and slowly shift my weight to the rear of the ski, but as soon as I hit a ripple it would bounce like crazy.
    Last edited by dduck1628; 09-11-2009 at 08:26 PM. Reason: typo

  7. #7
    dduck dduck1628's Avatar
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    Quote Originally Posted by jtskier11 View Post
    If you dont have RE's. Now would probably be the time to get some.
    I'm afraid you may be right. Thanks for the response good to hear from experience. RE blocks and/or shimming the plate or something else I'm not aware of. I'm usually a bit cautions with my purchases and research the hell out of everything I do.

  8. #8
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    RE's...

  9. #9
    dduck dduck1628's Avatar
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    So it looks like the RE block offs are the cat's meow when it come to porpoising?

    Anyone shim one of these plates yet?

  10. #10
    Site Admin Green Hulk's Avatar
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    Quote Originally Posted by dduck1628 View Post
    So it looks like the RE block offs are the cat's meow when it come to porpoising?

    Anyone shim one of these plates yet?
    Yep, the RE's are the bomb but I'm out of stock for several weeks. Next best thing is the Riva pro series blockoffs.

    I would try adding .030 shims under the back of the plate.

    If you try shimming please let us know how it works out.

    Thanks

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