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  1. #1
    Site Admin Green Hulk's Avatar
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    IMPORTANT! 2018 & newer SVHO, this is a MUST READ! Remove flame arrestor ribbon disc

    I wanted to make you guys aware of an issue we had with our 2021 GP1800R SVHO last week.

    Greg was riding the ski and it lost power. Came home to do a compression test and cylinder #4 had 0 psi compression.

    We pulled the intake manifold off in the process of removing the head only to find the ribbon disc missing from it's mounting location and instead it was bouncing around inside the intake manifold.

    What happened is the rubber seal that held the ribbon came loose, got stuck between the intake valve and the seat and bent the valve. Easy fix! It could have been much worse, we were very lucky that no other damage occurred.

    Later that week our friend Brock brought us his 2019 FX SVHO to install some upgrades, including the Riva ribbon delete kit and to our surprise his ribbon disc was cocked sideways and pushed into the intake manifold with hardly any pressure from one finger. This was a bone stock ski!!

    I used to not recommend the ribbon delete on 2018 and newer skis because the ribbon is larger than prior years and flows more air. Now, due to these incidents, I highly recommend doing the ribbon delete on Stage 1+, Stage 2 and Stage 3 skiís.

    On stock skis a quick fix would be to use a short self tapping screw and run it through the manifold into the ribbon on the opposite side of the ridge in the manifold.


    If you look at this picture, you will see there is a ridge on one side that holds the ribbon in place. I don't like this design, if Yamaha would put a ridge on both sides it would securely hold the ribbon from dislodging and causing such issues.

    Many of you guys that aren't getting the RPM that you should, your SVHO engine may already have a ribbon that's dislodged and blocking airflow. Check it asap!!!

    Greg will be dropping a video this week about this issue and we will post it here.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    Last edited by K447; 11-22-2021 at 06:09 PM.


  2. #2
    Site Admin Green Hulk's Avatar
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    This is the ribbon delete kit needed for 2018 and newer SVHO skis



    RIVA YAMAHA 2018 & Newer SVHO INTAKE MANIFOLD UPGRADE KIT

    RY12080-IMUK
    Our Intake Manifold Upgrade Kit enables your SVHO engine to produce more horsepower by delivering increased air flow and boost pressure (+1lb). Precision machined billet sleeve directly replaces restrictive mesh element that is prone to becoming dislodged in OEM plastic intake manifold. Provides imp...
    $149.95
    Add To Cart

  3. #3
    Mike1646's Avatar
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    What a coincidence, Iím receiving my kit today. I had a feeling that there was a possibility of that happening.

  4. #4
    Site Admin Green Hulk's Avatar
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    Quote Originally Posted by Mike1646 View Post
    What a coincidence, I’m receiving my kit today. I had a feeling that there was a possibility of that happening.
    Good move! Anxious to hear if your ribbon was also dislodged.

  5. #5

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    Thanks Jerry for the info. I will be ordering the delete kit from you. I donít want to leave that to chance.

  6. #6
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by Green Hulk View Post
    Ö if your ribbon was also dislodged.
    Can you post a link to the correct/current instructions for the IMUK with SVHO plastic intake manifold?

  7. #7
    Site Admin Green Hulk's Avatar
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    Hereís another one caught just in time
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  8. #8
    Site Admin Green Hulk's Avatar
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    Quote Originally Posted by K447 View Post
    Can you post a link to the correct/current instructions for the IMUK with SVHO plastic intake manifold?
    Good idea Keith, here are the instructions

    https://rivaracing.com/file/7427-RY1...e+Kit+SVHO.pdf

  9. #9
    Site Admin Green Hulk's Avatar
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    And another
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  10. #10
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    30hrs, stock 2019 GP , starting to dislodgeÖ I caught it while installing delete kit and tapping for blowoff fitting

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