gsx rave valve problem

[rdogg]

Hi Guys I have a 96 gsx 787 that I just had the motor rebuilt in because one of the rave valves broke off and hit the top of my piston.I was wondering if anyone could tell me if there is such a thing as an oversized rave valve that I could get or would one off of a snowmobile fit a little tighter.If not is there any other way to take some of the play out of the rave valves as the holes seem to be wore and there is a lot of play in them.I dont know if this caused the failure of the rave valve but Im thinking I should try something to tighten them up.Any help would be appreciated.Thanks for your help.

 

[Bills86e]

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. A large wire wheel also works real well. 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.
A loose fit is nessesary and normal though. The valves get very hot and expand, so loose clearances are necessary. But if the shafts have any wear on them, or the holes in the housings are getting oval shaped, you need to replace them. An up-grade "slotted rave" is now available and works excellent! Bills86e

 

[rdogg]

thanks for your response Bills86e.Would you happen to know where I could purchase the slotted rave?

 

[seadooya]

ebay or, i got one right here...pm if interested.

 

[rdogg]

Thanks for the replies guys,Would I have to modify anything on my machine to use the upgraded valves?