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  1. #1

    Question Decided on a beautiful brand-new 2020 Yamaha GP1800R SVHO, have some questions.


    Pulled the trigger on the 2020! Got it in Saturday and have already put about 7 hours, absolutely love it. Cuts chop surprisingly well and damn does it go on the throttle. I'm already looking to make some mods on it to make it even better, hoping to hit around 80mph by the end of the summer if my wallet allows. Right now I've decided on a "modified" RIVA stage 1 plus kit.

    I'm not really looking to go too far over 8000rpms this year for warranty's sake, and I the Map-X will most likely be my final purchase. So far my first mods I've decided on will be the RIVA Power Filter (https://rivaracing.com/i-24075395-ri...ilter-kit.html), RIVA Blow-off valve (https://rivaracing.com/i-17283803-ri...valve-kit.html), and the RIVA Rear-Exhaust (https://rivaracing.com/i-17283803-ri...valve-kit.html).

    I'm going to hold off on the tune until I run on just these mods for a while, but wanted everyone's opinion on them. I'd prefer to self-install, but I'm not fully sure if the rear-exhaust and the blow off valve are in my realm of doing so. Is anyone else on Allatoona in Georgia who has any experience?

    I saw on a thread that the RIVA engine breather kit leads to oil deteriorating significantly faster, is this true? I'd prefer keeping it on a Stage 1 tune vs the plus if I have to change oil every 25 compared to 50 hours. If I did install, I would put not a oil catch as well.

    Overall, just wanted to say happy to be part of the community with my own ski, and wanted advice if anything else needed to be done, and advice on my mod plan!
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    Last edited by bro55; 04-29-2020 at 03:58 PM.

  2. #2
    Click avatar for tech links/info K447's Avatar
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    Welcome.

    I have a pair of 2017 GP1800 SVHO with MapTunerX Stage 1 Plus tunes. Well over 200 hours on each.

    By far the most effective upgrade is not the exhaust, not the cold air intake, nor the blow-off valve.

    Install the Riva Stage 1 tune and you will have the added engine power and mid-range throttle response will be even stronger than stock.

    IIRC Riva has a 'normal' Stage 1 and 'Low Octane' Stage 1.
    Low Octane means 91, while the normal tune wants 93.

    I use the Stage 1 Plus 'Low Octane' tune, which wants 91 octane.
    I ran with the 8000 RPM limit version of the tune for a couple of summers, now we have the 8300 ish RPM limit tune installed.

    The Plus tunes are meant to be paired with specific engine hardware upgrades. The tune must match the actual engine configuration.

    For a totally stock SVHO engine with no changes to air intake, that would be Stage 1 tune without the Plus.

    Later when you install air intake upgrades you can switch to the Plus tune of choice.


    After the tune, the next significant performance increase would be a Solas impeller.


    I route the crankcase oil vent factory hose to the engine air intake. After almost 200 running hours I removed the intake to do some other work. There was only the smallest amount of liquid oil in the lowest region of the air intake duct. A few drops, maybe. Wiped it away, and have no interest in installing a catch can breather.

    I am unaware of ANY change in oil lifespan related to using or not using an oil catch can.
    I change oil per the owner's manual every 50 hours.
    I also change the oil filter with every oil change.


    I do not yet have a blow-off valve. No performance gain. While it might extend supercharger clutch life (how much, for us, is unclear) the BOV requires removing the intake manifold from the engine, drilling and tapping for a pressure hose barb, then reinstall everything. Which I could do, but the BOV is just not a really compelling upgrade. For me.

    We ride a mix of rough and non-rough water, and so far only one supercharger clutch has failed at 222 running hours. Replacement took a few hours, then it was ready for the water again. The other GP1800 with similar hours still has the original clutch.

  3. #3
    Ok awesome, love to here you're well over 200 hours! The exhaust and blow-off mods aren't really performance orientated, more of just a little added reliability and mainly the sound. I'm not quite interested in going to performance-centered until I get a lot more hours on the engine, but the tune will definitely be the the first change I make!

  4. #4

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    Good luck with your new ski, the colors and graphics remind me of the work of Pablo Ruiz Picasso.

  5. #5
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by bro55 View Post
    ... just a little added reliability and mainly the sound.

    I'm not quite interested in going to performance-centered until I get a lot more hours on the engine ...
    You have a factory warranty. The less you mess with the visual appearance of the engine, the less hassle there will be should you actually need warranty service.

    BOV install can (potentially) risk the warranty, as you are modifying the intake manifold. In addition to the BOV itself being quite obvious to whoever is servicing the engine.

    It is entirely unclear whether there is any 'added reliability' from adding a BOV to an otherwise totally stock engine. Perhaps, maybe, if riding fast and frequently in very rough water. Maybe. Right now I have two GP1800 with plenty of hours. One now has a new clutch, the other has the factory original. No BOV on either.

    How many hours are you expecting to ride in the next few years?


    Same for rear exhaust. Obvious modifcations can lead the dealer (or the Yamaha warranty office) to suspect other changes may have been done.


    MapTunerX tune can be restored to factory tune in minutes. If you select an 8000 RPM performance tune the ECU will not trigger any suspicions if you revert to the factory tune prior to dealer/warranty service.




    Sound? A friend has GP1800 with rear exhaust. Riding behind or near him, just more noise. Sitting on the seat, he cannot hear the exhaust at speed, too much wind noise.

    Myself, I do not see the point. I would be happy with less noise from the exhaust. I do not care whether other people are 'impressed' by how my watercraft sounds. At 70+ mph the exhaust sound is completely unimportant. There is no performance gain from exhaust mods.

    To install it you are making a large HOLE in the rear of the hull. Mess the install up and it could be a real problem.
    Last edited by K447; 04-29-2020 at 10:17 PM.

  6. #6
    Quote Originally Posted by K447 View Post
    You have a factory warranty. The less you mess with the visual appearance of the engine, the less hassle there will be should you actualy need warranty service.

    BOV install can (potentially) risk the warranty, as you are modifying the intake manifold. In addition to the BOV itself being quite obvious to whoever is servicing the engine.

    It is entirely unclear whether there is any 'added reliability' from adding a BOV to an otherwise totally stock engine. Perhaps, maybe, if riding fast and frequently in very rough water. Maybe. Right now I have two GP1800 with plenty of hours. One now has a new clutch, the other has the factory original. No BOV on either.

    How many hours are you expecting to ride in the next few years?


    Same for rear exhaust. Obvious modifcations can lead the dealer (or the Yamaha warranty office) to suspect other changes may have been done.


    MapTunerX tune can be restored to factory tune in minutes. If you select an 8000 RPM performance tune the ECU will not trigger any suspicions if you revert to the factory tune prior to dealer/warranty service.




    Sound? A friend has GP1800 with rear exhaust. Riding behind or near him, just more noise. Sitting on the seat, he cannot hear the exhaust at speed, too much wind noise.

    Myself, I do not see the point. I would be happly with less noise from the exhaust. I do not care whether other people are 'impressed' by how my watercraft sounds. At 70+ mph the exhaust sound is completely unimportant. There is no performance gain from exhaust mods.

    To install it you are making a large HOLE in the rear of the hull. Mess the install up and it could be a real problem.
    I it appreciate man, those are some really good points. Seems like the 8000rpm tune is the right way to go.

  7. #7
    MSX 150 guy lives on Mr. GP1800's Avatar
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    If you want more sound look at the TJ exhaust mod. It costs about 2 bucks for a pvc pipe cap and that’s it.

    I have a stage 1+ tune that’s limited at 8000. I run 78 mph consistently. If you want bang for your buck mods get the air intake ribbon delete and solas prop. Then the tune.

  8. #8
    The 19's and 20's are setup pretty well with the updated ride plate and intake grate. I'd go ahead and do the air intake now in the first year.

    Since the through the hull exhaust is pretty permanent, I'd suggest eliminating that top resonator in your exhaust first and see what you think.

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  9. #9
    Saum700p's Avatar
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    Those mods are great, I have done them on both of my skis. But you are not going to unlock any power until you tune the ski. It will be factory speed limited. I suggest the air intake and filter, rear exit exhaust, and a tune / impeller combo of Dean's team. That way they are a matched pair. You'll be looking at 80ish mph 8,000 that way. A ribbon delete is the one thing I would add if thats in your realm of knowledge to install, good for another lb of boost.

  10. #10
    Man beautiful ski! I would do the tune first otherwise you’re held at 68/69 no matter what you do.


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