Snowmobile Exhaust RAVE Maintenance
When was the last time you cleaned your RAVE valves? What's a RAVE valve you say? Boy...you really do need help!
Your RAVE valves (R.A.V.E. stands for Rotax Automatic Variable Exhaust) are those big bulging black caps with the red screw in the center, mounted to the front of the cylinders just above the exhaust ports on many Ski-doo models.
What they do in short, is modify the size of the exhaust port to boost responsiveness and power at the low-and mid-rpm ranges.
Taking apart your R.A.V.E. valves is not a big deal and should be done at least every 1000 miles (I prefer every 500 miles).
Once you get the hang of it, you'll find that this takes very little time. By doing it often you will also find that it will not only keep your sled running at its peek, but also aids in the cleaning the next time.Below are simple step-by-step instructions for the removal and cleaning of RAVE valves.
R.A.V.E. Valve Maintenance:
- Remove RAVE caps (via outside clips), being careful not to lose the coil spring inside the cap. DO NOT TURN THE RED SCREW ON THE CAP.
- Slide Ty-Wrap from rubber bellows. (Sometimes this can be re-used if done carefully but replacement is probably the best bet. Ski Doo makes a re-usable spring that will take the place of the Ty-Wrap and can be ordered from your dealer.)
- Slide rubber bellows back and unscrew the plastic disk. There is no need to remove the bellows completely from the RAVE housing.
- Next remove the two Allen head bolts (previously blocked by the Disk) using a 5mm Allen wrench and take the cast RAVE housing off, being careful not to tear the gasket. (You will need to replace the gasket during reassembly if you do.)
- Slide the RAVE valve out. This may be difficult if poor maintenance to the valves have preceded. Soaking with kerosene or carb cleaner can help loosen the grunge. I have seen some RAVE valves stuck badly enough that they had to be pried out. Be careful not to loose the rubber "O" ring on the shaft.
- Clean the RAVE valve, bellows, housing and all other parts. Mineral spirits or kerosene will help remove any oil/sludge that may have built up. The use of soft wire wheel to remove carbon deposits on the Valve itself will speed things up and make life a lot easier. Don't forget to clean the RAVE slot on the cylinder. Some spray carb cleaner and a screwdriver with a rag over the blade will get the job done.
- Reassemble in reverse order. The RAVE valves are marked "TOP" So it's fairly "goof proof" reinstalling them.
Some tips on maintaining R.A.V.E. Valves:Using a good synthetic oil will cut you RAVE maintenance in half.
Drilling a 7/8 hole in the top of you RAVE caps will allow you to inspect the valves easily and won't hurt the operation of the unit. You can observe the operation of the valves if your sled is on a warm-up stand or you can simply reach in with your finger or screwdriver and move the valves manually to confirm they are not stuck.
Before starting disassembly, I like to mark the position of the RAVE adjusting screws with a permanent marker in relation to the slot on the RAVE caps. That way if the screws are accidentally turned, you can easily put them back to their proper position.
ConclusionWith regular maintenance and a bit of practice, you can complete this task in about 20 minutes. Once done, your power should be improved and you should have no problem spanking your buddies' sleds again in those ever so common grudge matches.
(Click on the photos for larger, captioned views.)