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  1. #11
    Site Admin Green Hulk's Avatar
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    Dreadknotz and Supertoyz, 100% without a doubt being on the limiter will cause a bounce. This is common knowledge.
    May not make sense to you, but it makes perfect sense. Your throttle body is basically closing and opening on the limiter and this oscillation causes a bounce.

    If being on the limiter is not your bounce issue then definitely check your hull for straightness. This is easily done using a straight edge.


  2. #12
    Quote Originally Posted by Green Hulk View Post
    Dreadknotz and Supertoyz, 100% without a doubt being on the limiter will cause a bounce. This is common knowledge.
    May not make sense to you, but it makes perfect sense. Your throttle body is basically closing and opening on the limiter and this oscillation causes a bounce.

    If being on the limiter is not your bounce issue then definitely check your hull for straightness. This is easily done using a straight edge.
    Never said being on the limiter couldn't or wouldn't cause bounce.....makes perfect sense. Just not if you're nowhere near the limiter which appears to be the case with many of the people complaining about the issue. The hull not being flat also makes sense but I haven't checked it since there's not much I can or would do about it. That would be a sell it and move on solution.

    The only reason I bit on this thread was because I have the Deans Cut plate and I have bounce. It had been recommended to me that I get a Riva plate and it would solve the problem however from the forums and this thread I know people are having the same complaints with the Riva. Rev limiter is certainly a possible cause for some, if you're hitting it....for others who aren't, the hull problem is another possibility. For me I'm not convinced the Riva plate would solve my problem. I may try the 2022 Yamaha plate once I see it and hear some feedback. Either that or just keep it under 70 until I can get my hands on a 2022 or 2023 (hoping the colors improve).

  3. #13
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by Supertoyz View Post
    … The hull not being flat … I haven't checked it ….
    If the hull is not correct then you can stop looking for ride plate solutions.

    If I had an FX that was porpoising despite running well below the RPM limiter * I would certainly spend some time with a straightedge checking the lower hull profiles, especially the back half.

    * Sometimes, somehow, the RPM limit on the installed flash tune is not the RPM limit the rider thinks is installed.

    Happened to me once, somehow the tune I actually programmed in was not the tune as thought I had selected. Took a while before I eventually tried re-installing ‘the same’ tune and the correct tune was then installed. Had me confused for a while, that.

  4. #14
    Quote Originally Posted by K447 View Post
    If the hull is not correct then you can stop looking for ride plate solutions.

    If I had an FX that was porpoising despite running well below the RPM limiter * I would certainly spend some time with a straightedge checking the lower hull profiles, especially the back half.

    * Sometimes, somehow, the RPM limit on the installed flash tune is not the RPM limit the rider thinks is installed.

    Happened to me once, somehow the tune I actually programmed in was not the tune as thought I had selected. Took a while before I eventually tried re-installing ‘the same’ tune and the correct tune was then installed. Had me confused for a while, that.
    Agree with all of your statements, I'll check the hull eventually. I'm probably avoiding the answer since I'd never waste the money to fix it if the hull is cupped. In my scenario I don't believe the rev limiter is an option because mine starts to bounce at 8,000 RPM. If it was due to a rev limiter then it wouldn't continue on to 8500 RPM. Limiter is supposed to be at 8750 but who knows, maybe it's only at 8500. It just wouldn't explain why it starts to bounce at 8,000.

    Based on Kevin's report of the 2022's the change in hull attitude (nose up) is significant due to the new ride plate. Even if mine and others porpoising is due to hull cupping I still wonder if getting the bow higher with the new ride plate might lift the problem area out of the water eliminating the bounce?

  5. #15

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    Are you able to advise what areas I should be checking Jerry?

  6. #16
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by Supertoyz View Post
    .

    Based on Kevin's report of the 2022's the change in hull attitude (nose up) is significant due to the new ride plate. Even if mine and others porpoising is due to hull cupping I still wonder if getting the bow higher with the new ride plate might lift the problem area out of the water eliminating the bounce?
    The 2022 FX hull is also a different material, possibly produced using a new-for-the-2022-FX-model press mold for the SMC. Different hull material means different manufacturing process with different QA methods and possibly different ‘acceptable variation’tolerance’ targets.

    Yamaha may have encountered a problem with consistency during manufacturing of the 2019-2021 era FX hulls.

    Until a bunch of 2019-2021 FX owners do some hull bottom checking with straightedges and report back, we (and the FX owners) will just be guessing as to why some of those FX hulls porpoise more than others.


  7. #17
    I am starting to wonder about Yamaha's decision to leave Nanocell material of the FX hull from 2019-2021 and move forward in 2022+ with the SMC material. Maybe the bounce being caused from inconsistent hull fabrication was the underlying factor in their decision.

    Potentially the hull could have been flexing while at speed (> 68 mph) and reverberating at high speed from the material type. Going to the thicker and stronger material eliminated this occurrence.

    Just throwing out theories.
    Last edited by Dreadknotz; 11-01-2021 at 07:38 AM.

  8. #18
    Site Admin Green Hulk's Avatar
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    Quote Originally Posted by Jaycee84 View Post
    Are you able to advise what areas I should be checking Jerry?
    From the rear of the ski up about 4'
    Use a 4 foot long straight edge ruler. Just place it on the bottom of the hull back to front and look for daylight between the hull and ruler. Seeing a big gap would indicate a wavy hull. I will add that this is a very rare issue.

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