IMPORTANT! 2018 & newer SVHO, this is a MUST READ! Remove flame arrestor ribbon disc

[K447]

The IMUK kit for the SVHO plastic manifold is what you have, correct?

You want to use the IMUK tool on the second manifold to install a second sleeve.

[kawa900stx]

I'm a little confused. I have a 2018 GR1800 and I thought the ribbon was molded into the plastic intake thus requiring you to use the hole saw to cut it out. If its becoming dislodged, why couldn't we pull it out and use an insert like the 2017's? I just ordered a Fizzle and will do this as well since it'll be apart.

[hotbutta]

The hole is smaller than the ribbon.

[Green Hulk]

Does this happen on the 2018 HO as well? I know it’s a different intake manifold. But it’s still plastic. So any idea if this has happened to those manifolds?

its not an issue on the HO

[Green Hulk]

Add another to the list

[BB63Squid]

I purchased a 21 FX Limited last year and have ~ 15 hours on it.

I just ordered the Riva delete kit. I will post if it looks like the ribbon was starting to work it's way loose.

Thanks for the heads-up!

[jdarling2016]

I have a 2021 GP1800R SVHO, completely stock other than a BOV. Would you recommend the Intake Manifold upgrade kit (Ribbon Delete) or would you not worry with a stock ski? If it is recommended would I need to tune the ski after completion? Please give me a simplified answer because I'm pretty new to all this stuff LOL

[DavidH]

Do the ribbon delete. It is an issue weather you are modded or stock. If you can afford the Riva flash do it too, but if you can't the ribbon delete is fine to do without any other modification-- it is a damage control prevention.

[lungs414]

Would this be covered by Yamaha's warranty? Also is there any history of Yamaha doing recalls? I'm in NY and it would suck to have this happen during riding season, since if I had to bring it to dealer the wait for a repair would wreck the riding season. Also I realize a lot of guys on here work on their own skis, so it definitely makes sense for them to take a look. I don't plan on modding my '21 FX SVHO but this concerns me for the reasons I stated. I have extended warranty and don't want to deal with hassle of explaining whyI did something something bad happens. I know it wouldn't affect the entire warranty coverages, but I would like the engine covered for the next 4 years, don't want to give them an out just in case. What power gains are had by doing the delete?

[K447]

Would this be covered by Yamaha's warranty? Also is there any history of Yamaha doing recalls?

I'm in NY and it would suck to have this happen during riding season, since if I had to bring it to dealer the wait for a repair would wreck the riding season.

Also I realize a lot of guys on here work on their own skis, so it definitely makes sense for them to take a look. I don't plan on modding my 2021 FX SVHO but this concerns me for the reasons I stated.

I have extended warranty and don't want to deal with hassle of explaining why I did something [if] something bad happens. I know it wouldn't affect the entire warranty coverages, but I would like the engine covered for the next 4 years, don't want to give them an out just in case.

What power gains are had by doing the delete?

Removing the flame arrestor disc (aka ribbon disc) from inside the SVHO plastic intake manifold does not by itself create much of a performance gain. The performance gain happens when the ribbon delete is combined with an aftermarket ECU tune, which is matched to the modified air flow through the engine. For the Riva MaptunerX SVHO tunes that would be the Stage 1 Plus tune.

Removing the disc can change the balance of air delivery to the engine cylinders. In the pre-2018 engines with a metal intake manifold the center two cylinders would receive more air flow with the ribbon deleted (thereby casing those two cylinders to run somewhat ‘lean’) so the aftermarket tunes are configured to compensate by providing a matching increase in fuel mixture to the center two cylinders. The result is that the tuned engine runs with near optimal fuel ratio in every cylinder and provides more power overall.

If your SVHO engine is completely unmodified and has no indication of being anything other than factory stock then a failure of the flame arrestor disc would be covered under Yamaha’s engine warranty. Presuming of course that the machine has not been abused in some other manner.

Since this is a performance oriented PWC forum the majority of SVHO owners that go to the trouble to remove the ribbon disc will combine that change with an aftermarket ECU tune. The SVHO engine responds remarkably well to the combination.

Warranty work, should it be required due to a ribbon disc becoming dislodged inside the intake manifold, would likely happen during the riding season. And probably wait in the dealer service queue for longer than you would want during the warm weather.

What I have not seen is suggested reinforcement or modifications to help retain the ribbon disc in factory position. This would seem quite possible, but the work required to do a reinforcement is probably at least as much as removing the ribbon disc once you have the plastic intake manifold on the work bench. At which point you have already potentially affected the warranty, and more so with the disc reinforcement modification installed.

For many SVHO owners on this forum, the preferred approach is to remove the flame arrestor disc, install the IMUK kit, and simultaneously (if not already done) upgrade the ECU tune. The combination works well, maintaining fuel mixture ratios and providing increased acceleration and noticeable top speed gain. Engine RPM can remain within the 8000 maximum range that Yamaha wants to see in the ECU log for warranty purposes.