Sorry Quick ? About 1997 787 Rave Valve

[Cid6.7]

Hey Guys Im new here & I dont really have a problem but just a quick question..Im cleaning the rave valves wich aint that bad considering the age but when putting them back together screwing the top black "plunger" back on how far do I tighten it ..? Just snug it down hand tight ..?

Thanks I'll enjoy it here as I like tinkering & making things work better..lol

 

[kustomkarl]

Welcome to the seadoo forum Cid6.7. Her is everything you ever wanted to know about your RAVE valves....Enjoy;

RAVE VALVE annual cleaning

________________________________________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 holds 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, if so equiped. 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.

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.

Karl

 

[Cid6.7]

Soooo just hand tight then?..lol :cheers:

 

[kustomkarl]

Uh...I use wrenches when I tighten things that have lots of vibration... You don't want to have it come off. Snug it down, it needs to be tight, but not tight where it's gonna break.

Karl

 

[Cid6.7]

Okey Doke Thanks :cheers:

 

[Jaz]

I didn't know how the Mods here feel about new thread clutter (I am a Mod at an investment website and I can't stand new threads created when an old one on the same topic could be posted in...don't know why that's a pet peeve of mine), anyways, so I thought I would rehash this one since my issue is of the same equipment.

I have a '97 GTX and for some strange reason the very top part of the RAVE valve seems to have melted. I don't know when it happened. I have had it stored all winter in my garage, so I don't know if happened during the last summer season while we were running it, or if it happened sometime over the winter while being garaged.

A brief explanation of what it looks like. It appears as though the top part melted, the part where the red adjustment head thingy (that's a technical term if you're wondering) screws into the body part. The upper body part of it is what's melted. So, without that upper part to hold in the red screw adjustment head, the spring seemed to have blown it out of the body.

What's also even more strange is that the top part of the bellow is missing. I don't know if it just disintegrated or incinerated altogether, or it has fallen somewhere into the hull and I can't see it. Regardless, it's not attached to the bottom part of the bellow.

What I also noticed is that on the side of the exhaust that's next to the RAVE valve seems to have oil residue on it. Like it was being sprayed on from the RAVE valve. I don't know if that's significant. And I also don't know for sure if it's oil or that it's coming from the valve, although that is what I suspect in both cases.

So, my questions are: What could cause that upper part of that RAVE valve body to melt (I also forgot to mention that it's just the innards and no part of the outer body was melted)?

Or:

Could it have only melted when it was running or is it possible something happened to it while it was being garaged? Like maybe some gaseous leaking that cause pressure to build up and the incineration was by pressure release?

Thanks in advance for any insight.

 

[Chester]

I didn't know how the Mods here feel about new thread clutter (I am a Mod at an investment website and I can't stand new threads created when an old one on the same topic could be posted in...don't know why that's a pet peeve of mine), anyways, so I thought I would rehash this one since my issue is of the same equipment.

I have a '97 GTX and for some strange reason the very top part of the RAVE valve seems to have melted. I don't know when it happened. I have had it stored all winter in my garage, so I don't know if happened during the last summer season while we were running it, or if it happened sometime over the winter while being garaged.

A brief explanation of what it looks like. It appears as though the top part melted, the part where the red adjustment head thingy (that's a technical term if you're wondering) screws into the body part. The upper body part of it is what's melted. So, without that upper part to hold in the red screw adjustment head, the spring seemed to have blown it out of the body.

What's also even more strange is that the top part of the bellow is missing. I don't know if it just disintegrated or incinerated altogether, or it has fallen somewhere into the hull and I can't see it. Regardless, it's not attached to the bottom part of the bellow.

What I also noticed is that on the side of the exhaust that's next to the RAVE valve seems to have oil residue on it. Like it was being sprayed on from the RAVE valve. I don't know if that's significant. And I also don't know for sure if it's oil or that it's coming from the valve, although that is what I suspect in both cases.

So, my questions are: What could cause that upper part of that RAVE valve body to melt (I also forgot to mention that it's just the innards and no part of the outer body was melted)?

Or:

Could it have only melted when it was running or is it possible something happened to it while it was being garaged? Like maybe some gaseous leaking that cause pressure to build up and the incineration was by pressure release?

Thanks in advance for any insight.

It melted while it was running. You have to replace all of the melted parts and the RAVE valves plus the RAVE valve housings. They wear out and allow hot exhaust gasses to pass to (and melt) the RAVE piston.

Chester

 

[Jaz]

It melted while it was running. You have to replace all of the melted parts and the RAVE valves plus the RAVE valve housings. They wear out and allow hot exhaust gasses to pass to (and melt) the RAVE piston.

Chester

Thanks. Yeah, I took it into the shop and they are going to fix it. They had to have the parts shipped in from Canada. With the summer tune-up it's going to set me back around $550.

 

[Lightning546]

I had the same thing happen to me, what caused the problem is the gasket was installed incorrectly which allowed the exhaust gases to enter the bellows area and melt the cap.