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  1. #1

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    2021 FX porpoising Riva ride plate

    Anyone found a fix that works to stop this porpoising with the riva ride plate ?

  2. #2
    Quote Originally Posted by Jaycee84 View Post
    Anyone found a fix that works to stop this porpoising with the riva ride plate ?
    The porposing happens when your on the rev limiter sir. An increase in RPM or others solutions can be had to limit this.

  3. #3
    Site Admin Green Hulk's Avatar
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    Quote Originally Posted by Dreadknotz View Post
    The porposing happens when your on the rev limiter sir. An increase in RPM or others solutions can be had to limit this.
    I agree, 90% of the time being on the limiter causes the bounce.
    You can either have the limiter increased on your tune, or add some pitch.

  4. #4
    Quote Originally Posted by Dreadknotz View Post
    The porposing happens when your on the rev limiter sir. An increase in RPM or others solutions can be had to limit this.
    Quote Originally Posted by Green Hulk View Post
    I agree, 90% of the time being on the limiter causes the bounce.
    You can either have the limiter increased on your tune, or add some pitch.
    Not sure I agree, or I'm in the 10% that it doesn't apply to.

    I've been running a 2019 SVHO with a Deans Tune and modified ride plate and have also been struggling with porpoising over 70 mph. Talking with Dean about it last year they had the same issue on some models and were testing shimming of the ride plate. I bought and installed some of their shims late last year and thought I'd successfully eliminated most of the porpoising.

    Over the winter I installed a pump wedge hoping to get the bow up a little more and maybe gain 1-2 mph. This season it ran the same 77 mph at 8500 and the porpoising was back (or never went away). I removed and reinstalled the shims with not much of a difference either way.

    Talking with Dean this year he said they found some hulls to not be level on the outside surface. I haven't checked mine yet.

    Then I was talking with Kevin Shaw about pre-ordering a 2022 and my issue with porpoising on my 2019. He was confident that replacing the Deans plate with a Riva would solve it. I'm skeptical of this because I know others are having the same issue with the Riva Plate.

    I'd mentioned the Rev Limiter theory to Dean and he scoffed at it. I agree it doesn't make sense, at least for me because my limiter is supposed to be set at 8750 and I get bounce from about 8,000 up to my max of 8500. I may try a 2022 ride plate when they're available or just buy a 2022 SVHO and hopefully be done with it.
    Last edited by Supertoyz; 10-26-2021 at 04:29 PM.

  5. #5
    Quote Originally Posted by Supertoyz View Post
    Not sure I agree, or I'm in the 10% that it doesn't apply to.

    I've been running a 2019 SVHO with a Deans Tune and modified ride plate and have also been struggling with porpoising over 70 mph. Talking with Dean about it last year they had the same issue on some models and were testing shimming of the ride plate. I bought and installed some of their shims late last year and thought I'd successfully eliminated most of the porpoising.

    Over the winter I installed a pump wedge hoping to get the bow up a little more and maybe gain 1-2 mph. This season it ran the same 77 mph at 8500 and the porpoising was back (or never went away). I removed and reinstalled the shims with not much of a difference either way.

    Talking with Dean this year he said they found some hulls to not be level on the outside surface. I haven't checked mine yet.

    Then I was talking with Kevin Shaw about pre-ordering a 2022 and my issue with porpoising on my 2019. He was confident that replacing the Deans plate with a Riva would solve it. I'm skeptical of this because I know others are having the same issue with the Riva Plate.

    I'd mentioned the Rev Limiter theory to Dean and he scoffed at it. I agree it doesn't make sense, at least for me because my limiter is supposed to be set at 8750 and I get bounce from about 8,000 up to my max of 8500. I may try a 2022 ride plate when they're available or just buy a 2022 and be done with it (hopefully).
    Thanks for engaging. It is a relief to see experienced/knowledgeable individuals share their experiences.
    Would you mind listing ALL your Mods in detail?

    I too have resorted to the 'Rev limiter" theory. I oddly have the bounce at top speed on Glass conditions ONLY. All conditions outside of this I have yet to experience the bounce. I have seen where some people have reported being thrown. I guess its my weight and height ( 275lbs at 6'7") that has saved me. I am just unsure , I have heard soo many conflicting stories. But one thing for sure, People have reported a consistent sentiment as you stated from Deans Team himself.

    Maybe 2022 Ride plates are the solution for 2019-2021, I doubt they are tho, as with the GP 1800 vs GP 1800r , Yamaha has a tendency to make a copycat of the RIVA Product.
    Thing is, I just doubt Yamaha would release a product that would bounce at limiter or topspeed to the general public.

    To take it a step further, with your Deans Team thought process, If Shaws/Green Hulk team are correct, then the 2022+ FX SVHO have a raised rpm with RIVA copycat rideplate. HMMMMmmmmm

  6. #6
    Quote Originally Posted by Dreadknotz View Post
    Thanks for engaging. It is a relief to see experienced/knowledgeable individuals share their experiences.
    Would you mind listing ALL your Mods in detail?

    I too have resorted to the 'Rev limiter" theory. I oddly have the bounce at top speed on Glass conditions ONLY. All conditions outside of this I have yet to experience the bounce. I have seen where some people have reported being thrown. I guess its my weight and height ( 275lbs at 6'7") that has saved me. I am just unsure , I have heard soo many conflicting stories. But one thing for sure, People have reported a consistent sentiment as you stated from Deans Team himself.

    Maybe 2022 Ride plates are the solution for 2019-2021, I doubt they are tho, as with the GP 1800 vs GP 1800r , Yamaha has a tendency to make a copycat of the RIVA Product.
    Thing is, I just doubt Yamaha would release a product that would bounce at limiter or topspeed to the general public.

    To take it a step further, with your Deans Team thought process, If Shaws/Green Hulk team are correct, then the 2022+ FX SVHO have a raised rpm with RIVA copycat rideplate. HMMMMmmmmm
    I'm anxiously waiting to see what the 2022 Ride Plate looks like because from Kevin's description it sounds like it has a small radiused edge at the back and what I interpreted as two small vertical stabilizers. I ordered a 2022 Ski for a second machine and was having a lot of trouble deciding what to get. I discussed my complaints of the 2019 FX with Kevin several times and he's very convincing that the 2022 Hull and Ride plate has corrected them.

    My mods are pretty simple, all I have is the Deans Team FX starter kit which is essentially the same as Riva's Stage 1+ without the sponsons. It's a tune, impeller, modified ride plate, cooling strainer and Riva Power filter kit. I also cut out the center bar of the strainer and filled the voids in the back of the strainer per Deans instructions.

    I ride mostly with a buddy on his RXTX 300 (similar mods) and the FX seems consistently quicker out of the hole but they are even on top at 77 mph. The embarrassing difference is his is dead smooth at WOT and I feel like I'm riding a galloping horse. Back off below 70 mph and it stops.

  7. #7
    2021 FX Stage 1 Plus ran 79.4 GPS at 8650 rpm on an flat lake. no Problems with that Riva Rideplate

  8. #8
    cmherrera's Avatar
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    I'm waiting to see what the 2022 Ride Plate looks like also.

  9. #9

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    my 2019 porpoised badly above 65 - tried riva plate - better but still way to much - shimmed every which way - finally cut off extension off riva plate and was better.

    In the end - the hull was the issue - you could see the ripples/waves from wear - hull was terrible - turned it back to stock and sold it. Check hull for flatness.

    Good Luck

  10. #10
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by tchies View Post
    my 2019 porpoised badly the hull was the issue - you could see the ripples/waves from wear - hull was terrible

    - Check hull for flatness
    This is a manufacturing quality/consistency problem?

    The hull bottoms from the factory are deformed, or become non-uniform in use?

    I have not seen others reporting on FX hull non-straightness.

    What areas of the hull bottom did you notice had the waves?


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