Fx 140 Speed Question???

[YoYamma]

Re: Fx 140 Speed Question???

Okay thanks for the input, will talk to our dealer about installing some of these kits, once I get a total cost I can decide whether it's worth the $$$.

[YoYamma]

Re: Fx 140 Speed Question???

Both of our 140s are maxing at 9,200 rpm, this is interesting.
We removed one air filter today and it still looks llke new.
These OEM filters were replaced a few months ago; I see no signs of oil in them whatsoever. Just for kicks, we tested one of the FX 140's with no filter and it shot off like a rocket; solid 10 - 11 mph gain on the meter and a solid 10,000 RPM. This tells me the problem is just the airflow. I need to do more research on this... like, will the Riva Velocity Stack/Power Filter kit give us back the 10K RPM and keep it there? I'm surprised we are losing 800 rpm this is something Yamaha needs to address. Will the kit boost the performance or just a few rpms which would be a disappointment. I guess we could try it on just one ski first. Will the Riva kit void my Y.E.S. warranty? Can I just run the skis without an air filter? What about water intrusion... lots of questions.

[jkflow]

Re: Fx 140 Speed Question???

Keep in mind that the secondary function of the air filter is 'flame arrestor'. It is no big secret that as you decrease the air resitance any engine will increase in performance. In this case you are risking a fire or explosion running without:emoticonc .

That is why the velocity stacks require the additional flame arrestor i.e. you are essentially running without an air filter, all you have is a wire mesh that eliminates the danger.

I read somehwere else 'scratch my head' that the Yamaha engine electronic will adapt to the new air flow after a while and adjust the ignition sequence i.e. decrease performance to maintain the design parameters as much a spossible. Anyone with input on that one or is this just a myth?
That might explain what you have seen though, initial performance gain that later reduced, shouldn't be more than a couple of operating hours though.

[Technical Support]

Re: Fx 140 Speed Question???

No, the filter is just a filter. The flame arresotors are built into the stock stacks.

[YoYamma]

Re: Fx 140 Speed Question???

Tech Support, sorry don't know your name, can you give me an explanation of what the flame arrestor does on these skis, I think this applies to all boat engines, sorry I'm not a mechanic. I did notice a metal screen over the stock stacks, do the Riva trumpets have this also? No danger with the Riva kits, is there?

[Technical Support]

Re: Fx 140 Speed Question???

If there is a backfire through the intake, the flame arrestor breaks up the flame so it doesn't just fireball into the hull. It's just a metal mesh screen. It's a US coast gaurd requirement on all PWC.

[edisit]

Re: Fx 140 Speed Question???

Sorry to jump in here but doesn't the Riva and R&D power filters act as a flame arrestor since all airflow goes through it's metal mesh? Granted it is not a part of the intake.

This is what is on the island racing web site:

Designed to increase horsepower and torque throughout the RPM range on your FX140 or FX High Output. Riva's easily installed Velocity Stack Kit replaces the restrictive factory stacks providing improved throttle response and top speed. We highly recommend they be used with Riva's Power Filter to achieve maximum performance benefit. Kit includes four Velocity Stacks machined from billet aluminum that utilize o-ring seals and set-screws to lock onto throttle body and are anodized to prevent corrosion. Sold in sets of four.Riva's FX Power Filter is a direct replacement for the restrictive stock air filter in the OEM air box. Delivers increased airflow to engine providing improved throttle response, acceleration and top speed. Screen-type element will not soak up excess engine oil as does the OEM paper element that increasingly restricts performance.


NOTE: Power Filter required when using RIVA FX Velocity Stacks (part# RY1325-VSK) to meet U.S. Coast Guard flame arrestor requirements.

[YoYamma]

Re: Fx 140 Speed Question???

Ahhh, I see it says, "screen type element"... maybe it's simply an arrestor and not even a filter. Makes sense. I need to find out if this will void my warranty or not.

[Technical Support]

Re: Fx 140 Speed Question???

Yes any aftermarket part can void warranty coverage - it all depends on your relationship with your particular dealer.

[edisit]

Re: Fx 140 Speed Question???

Since I have no extended warranty that is not an issue for me. I have both the stacks and the power filter in my ski and love the performance gain. Is there a safety concern using these ugrades or a reduction in engine life?

[YoYamma]

Re: Fx 140 Speed Question???

Edisit, questions...
1. what is your exact model/year
2. what kind of gain did you get
3. are those the only mods you have?

[edisit]

Re: Fx 140 Speed Question???

Edisit, questions...
1. what is your exact model/year >>

FX140/2003

2. what kind of gain did you get >>

With a clogged filter I got 48 mph on GPS
With a clogged filter and Solas 13/19 impeller I still got 48 mph on GPS
With the new power filter, stacks, and Solas 13/19 impeller I got 55 mph on GPS and a lot more out of the hole acceleration

I never checked my ski on the GPS when it was new but my speedo would read 55-57 and now reads 60-64

3. are those the only mods you have?

Yes

[YoYamma]

Re: Fx 140 Speed Question???

Edisit, how many hours (approx.) have you put on the ski since
you added the stacks/filter?

[YoYamma]

Re: Fx 140 Speed Question???

Yes any aftermarket part can void warranty coverage - it all depends on your relationship with your particular dealer.

Care to elaborate on what you mean, my dealer and I have no relationship
other than they did my oil changes and sold me two new filters which are apparently having a negative impact on my performance.

[Technical Support]

Re: Fx 140 Speed Question???

It's self-explanitory. Some dealers overlook mods, others don't - you have to ask.