Rave Valve?

[joshsfzr400]

I own a 1997 seadoo challenger and I noticed that when I took off the cover on the 2 valves on the top of the motor (rave valve): I noticed that one was clean and the other had oil all over it. I was just wondering what can cause this and should I worry. If its something to address, where would I start??

 

[kustomkarl]

It sounds like the RAVE valve Bellows(rubber diaphragm) is leaking oil. The spring is either loose and needs a new one or the bellows are bad. Hold it up to the light and look for pin holes, or for a loose spring. Here is a good explanation and a maintenance recommendation too.The RAVE, (Rotax Adjustable Variable Exhaust) valves are located above the exhaust valve. There are 2 of them per engine. They are round with a red adjustment screw in the middle. It has a clip that holds it together. How they work is that they open the exhaust port larger as the engine rpm's increase. When the rpm's drop down so do the RAVE valves. They work on the principle of the pressure of the exhaust system. Rpm's increase, pressure increases and the valve opens, rpm's drop pressure drops, Valve closes. They should be de-carbonized annual. To disassemble the rave valves, remove the spring clip on top, remove the black cover. There is a spring under the cover. Remove the piston by turning it with a metric socket. On the bottom of the piston is the rubber "Bellows" be careful with the small retaining spring that hold the bellows on the piston. Remove the 2 allen screws that hold the base on the cylinder. Remove the base and gasket. The long valve won't fall in the cylinder just pull it out. There is an o ring under the base, on the shaft of the guillotine valve. Be careful to see how it came apart as it has to go back together that same way again. On the base, notice the notch that it is facing down. Clean all the carbon off the guillotine valve. I use carb cleaner and 400 grit paper. Check the bellows for any small pin holes. If so replace it. If not, reassemble it on the clean guillotine valve, and install it back on the engine the same way it came apart. The guillotine valve only fits one way. The one closest to the exhaust pipe will come off differently then the other one. You will have to remove the allen screws and turn the base so it clears the exhaust pipe. I would do one at a time in case you forget how it goes back together again. This way you can look at the other one and copy it. Do both engines 2 per engine. Take your time and if you have questions give us a shout. We'll be here to help you out.
If the RAVE valves are dirty it will not rev up correctly and could be causing your problem.

I hope this helps out.

Karl

 

[96gtxdess]

Hello, i have a 96 gtx 800, i just had the engine rebuilt and mechanic and my self were not sure where to turn the 2 red adjustsments on top of the rave valves, i was moving them around before i realized i should not have touched them, anyone have any ideas what the stock settings are, thanks p.s it now seems to bog in the lower rps a little then takes off, even out of the water you can hear the bog, thanks

 

[Gunsrunner]

I think most of us have them screwed all the way in, this will cause the raves to open later in the rev range and should give more torque for towing or holeshot. If you screw them out tops level with the black plastic edge, your raves will open sooner giving higher horsepower but lower torque so faster to top speed but less towing power and slower holeshot!!:cheers:

 

[kustomkarl]

Here is the correct adjustment of the RAVE valves The adjustment knob (the red cap) should either be screwed all the way in or flush to the top of the black ring of the cap. This will only affect performance, as far as how it jumps out of the hole or how well it runs for extended periods at WOT..

I hope this helps...
Karl