jetskiboy17
New member
what is and how does the rave and how does it work what mods does it have?
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the R.A.V.E. ?
- Thread starter jetskiboy17
- Start date
If I am not mistaken here, R.A.V.E. stands for "Rotax Adjustable Variable Exhaust" In other words - SkiDoo.
Thread moved to tech section.
-1CS
Thread moved to tech section.
-1CS
horkn
New member
1CrazySledder said:
dunno whether it is "adjustable" or "Automatic", but either way, it is a skidoo thing.
It does work pretty well, and some aftermarket companies have made cylinders that fit non skidoo's, that use the skidoo RAVE system.
it is basically the same as the SRX/ cat/ polaris setup but non servo controlled. A simple spring is what controls them. I had them on my 90 mach / plus, and the VES on my polaris xc600sp.
they do not self clean, but seem to not get plugged like the early polaris models. I put several thousand miles on my 617 RAVE powered 1990 Formula Plus and never had a gummed RAVE valve. that was using regular non synthetic special power valve oil as well.
My xc600sp with VES needs the expensive oil, and still needs cleaning in the beginning of every year.
It is indeed Rotax Adjustable Variable Exhaust. These are the round black with red insert things above where the exhaust manifold connects to the engine. They are spring loaded guillotine valves that raise and enlarge the exhaust ports on the engine. This allows for the engine to be tuned for both low and high rpm power.horkn said:
They are very easy to clean and adjust. Several magazines have included how-to's on cleaning these valves in past years. Such as this link http://snowmobile.off-road.com/snowmobile/article/articleDetail.jsp?id=195490
Bakemono
New member
You guys are right. Its, "Rotax automatic variable exhaust". It basically has a bellows in it that gets filled as the exhaust pressure builds. As that bellows gets filled, it forces a slide up.
Like Ding said, it gives the engine good torque down low, but when you reach high rpm it gives the effect of a bigger exhaust port, so you get flow and good high rpm performance too. This makes the engine run much more efficiently.
On a non-exhaust valve engine, when they design the ports they typically compromise between low end grunt and topend scream. However, with variable exhaust you get the best of both world and there is no compromise.
Cleaning them is actually really simple. Im not sure about RAVE, but with the VES system that Polaris uses, you remove 2 bolts and the whole valvebody slides right out, allowing you to easily clean the slide. You then lightly oil the slide, slide it back in the engine, tighten the bolts back up and you are done.
Its a very simple system. Its not as precise as electronic variable exhaust like what Yamaha used, but its very simple and very easy to maintain. The only thing that you ever really see go wrong with that kind of design is that you can sometimes get a pinhole or tear in the bellows and then it wont build up exhaust pressure and the valve wont open. The valve then builds up a lot of carbon because its no opening and it can be really hard to get out.
When I first bought the Polaris I have now, it had a torn bellows. I didnt know it until I went to clean that valve at the end of the season and found one of the valves to be much, MUCH dirtier than the other. Infact, the valve had so much carbon buildup that it was very difficult to get it out of the engine. After disassembling the valve, I found the torn bellows, replaced it and its been fine ever since.
Like Ding said, it gives the engine good torque down low, but when you reach high rpm it gives the effect of a bigger exhaust port, so you get flow and good high rpm performance too. This makes the engine run much more efficiently.
On a non-exhaust valve engine, when they design the ports they typically compromise between low end grunt and topend scream. However, with variable exhaust you get the best of both world and there is no compromise.
Cleaning them is actually really simple. Im not sure about RAVE, but with the VES system that Polaris uses, you remove 2 bolts and the whole valvebody slides right out, allowing you to easily clean the slide. You then lightly oil the slide, slide it back in the engine, tighten the bolts back up and you are done.
Its a very simple system. Its not as precise as electronic variable exhaust like what Yamaha used, but its very simple and very easy to maintain. The only thing that you ever really see go wrong with that kind of design is that you can sometimes get a pinhole or tear in the bellows and then it wont build up exhaust pressure and the valve wont open. The valve then builds up a lot of carbon because its no opening and it can be really hard to get out.
When I first bought the Polaris I have now, it had a torn bellows. I didnt know it until I went to clean that valve at the end of the season and found one of the valves to be much, MUCH dirtier than the other. Infact, the valve had so much carbon buildup that it was very difficult to get it out of the engine. After disassembling the valve, I found the torn bellows, replaced it and its been fine ever since.