someone explain rave valve to me

[brandon32689]

Hey guys so I got 2,96xps n I noticed the rave valve is unscrewed to flush el. We cleaned the raves on my uncles spx and noticed his is screwed in pretty far so we backed em.out to level today at lake ski kept bogging so we put them back how they were and it ran great. So what do they do that causes this and should I tinker with them.

 

[bigJake]

there is a great explanation here somewhere by kustomkarl or seadoosnipe on the RAVES but basically the red cap adjusts tension on the spring inside the cap which holds the rave valve closed. as exhaust pressure builds and overcomes the tension of the spring the rave opens and allows more porting of exhaust thereby allowing a higher rate of combustion which equates to more speed, the raves typically start to open at 4500 - 5000 rmp

 

[brandon32689]

okay so what would typically make the ski run better the caps flush or out a little or in a little? thanks

 

[bigJake]

the standard setting is flush but I would think it would be a matter of a little experimenting, if your springs have lost a little tension then you would probably have to crank them in a little to compensate. I don't know for sure but there is probably some correlation with how your carbs are adjusted and I think their peformance may also be affected by the adjustment on the water regulator. I think I read the raves and the regulator have to be working in sync for best performance but sorry I can't help with specific details.

 

[bigJake]

brandon, I found this on another website, it doesn't explain your bogging though:

"There is very little effect no matter where you set the spring rate by adjusting the red knob.

The adjuster affects when the valve opens, sooner or later as rpm rises. There are zero HP differences in any setting.

If you need more bottom end grunt, adjust them inward. That makes the exhaust port timing stay lower longer before the valve opens and raises the port timing.

If you play with the rave red knobs in conjunction with the red knob on the water regulator, you may see slight changes in the low to midrange power band.

A general rule is rave knobs in, water regulator knob out, or vise versa. "

 

[brandon32689]

Thanks man. Ya it wasn't bogging really just had weird take off n after putting them back how they were they ran great

 

[6KJR]

Its more about the power curve, not how much power is made. The engine puts out the power it has.

Change it and see if you notice. Put them all the way in and it will delay the power curve a LITTLE. To each their own. My 800 trippple sled has them IN, as to delay this power a little. It makes enough bottom end to rip the track off without having the valves open up sooner. haha.

 

[brandon32689]

Is it okay to put it all the way in? I just don't want the piston to somehow hit the rave

 

[JJinSC]

All the way in is fine. Adjusting the red knob has nothing to do with the valve's position. It only adjust the springs tension on the valve.

 

[brandon32689]

Oh okay then I may tweek w mine a little next time I'm out at lake.

 

[6KJR]

You giver. You may notice a slight change.