[BarkMulcher]

Where could I find the info on how the V.E.S works???
They have been around for a few years (new to me). But I would like to know the theory behind them. What they do, How, etc.

Thanks

I did search, but the info provided was a little...simple and plain []

 

[TheKuskokid]

Small exhaust ports = good low rpm performance and limiting of high rpm performance.
Big exhaust ports = good high rpm performance and kinda not so perfect low rpm performance.

VES is a blade that covers some of the exhaust port, effectively making it a small port. There is a hole drilled through to the combustion chamber that allows high pressure gas to act on a rubber bellows. A spring exerts pressure on the bellows keeping the bellows collapsed and the blade in the closed position. As your rpm increases the "pump-up" action of the small hole on the bellows begins to overcome the spring pressure, allowing the blade to move upward and out of the exhaust port, effectively increasing the port size. By the time you're at 7k rpm, it is almost all up.
The spring pressure can be increased by turning the blue thing in the center of the beehive. This delays the retraction of the blade. Good for drag racing.

 

[BarkMulcher]

thanks... But I want more technical data as well. I don't have no blue thing in my behive ('04 XcSp) is that on newer models?

 

[Thinksno]

Blue adjuster is old style. Pick up performance manual PN 9918586 at dealer.

 

[BarkMulcher]

Originally posted by Thinksno
[br]Pick up performance manual PN 9918586 at dealer.

I had to order that manual. Still waiting for it... think it's been 5 weeks now[!][!][!]

 

[edgex600rider]

Ya the blue adjuster was only on the early models. They didn't have them in 2002 I dont think. Mine has it and had wondered what adjusting it would do. I will mess with it this year to see what differences it makes all over the powerband.

 

[Memphis]

good

 

[Triple650Indy]

Originally posted by BarkMulcher
[br]thanks... But I want more technical data as well. I don't have no blue thing in my behive ('04 XcSp) is that on newer models?

Technical, like what, he just gave you the theory behind it, nothing fancy just the meat and potatoes.

 

[brnr17]

well i have an 01xcsp with the blue ones .... what way is what tho? i just bought the sled and one is turned slightly more than the other ... if u turn the clockwise what does that do? counterclockwise?

 

[TheKuskokid]

Lefty loosey, rightey tightey.

 

[weantright]

On my 1999 xcr440 adjusting these blue caps all the way (all in or holding on out) would push the power band up/down 500 RPMs. These 440 motors had maybe a 1000 RPM power band. Keep them dirty or tape them so they don't fall off. You will know when they fall out!

 

[BarkMulcher]

Originally posted by Triple650Indy
[br]

Originally posted by BarkMulcher
[br]thanks... But I want more technical data as well.

Technical, like what, he just gave you the theory behind it, nothing fancy just the meat and potatoes.

What kind of pressure does it take to move them? How does rpms effect them, Changing Rpm's etc. Spring rates?

[]

 

[chadd]

[/quote]

What kind of pressure does it take to move them? How does rpms effect them, Changing Rpm's etc. Spring rates?

[]
[/quote]
The only people that would know that information would be the engineers that designed the VES system. Also, I would imagine that the information would change based on the engine you are talking about. The pressure would depend on the material the bellow is made of, the weight of the valve, the area of the underside of the bellow, the spring rate of the spring, etc. Putting a stiffer spring in would require more pressure entering the bellow to raise the valve, hense raising the rpm at which the valve would begin to raise.

 

[BarkMulcher]

So I guess there isn't really any tech info around for these valves? Just the layman *How it works* stuff... that sux...

What would happen if I enlarged the 2 holes slightly in the valve? Would that effect the pressure?

 

[_FURF_]

Originally posted by BarkMulcher
[br]So I guess there isn't really any tech info around for these valves? Just the layman *How it works* stuff... that sux...

What would happen if I enlarged the 2 holes slightly in the valve? Would that effect the pressure?

that would allow less pressure to push the valves out. Thus, your top end would slow way down.

 

[chadd]

Originally posted by BarkMulcher
[br]So I guess there isn't really any tech info around for these valves? Just the layman *How it works* stuff... that sux...

What would happen if I enlarged the 2 holes slightly in the valve? Would that effect the pressure?

Just out of curiousity, what are you trying to accomplish by doing this? Getting more pressure to the valve would not give you more horsepower or anything, it would just cause the valve to open at a lower rpm. The same thing would be accomplished by putting a different (lighter) spring in, which would be considerably easier. If you go to too light of a spring, you are essentially making your motor a high port motor, and losing any advantage VES gives you. Does your motor have a dead spot somewhere in the powerband somewhere slightly before or after the valve moves? If so, changing the engagement rpm of the VES valves may gain you something. Otherwise, I doubt you will find much in the way of free horsepower. Now maybe if you piped or ported it, or ride at a high altitude, adjusting the valve would be beneficial. But on a stock sled, it is probably about as good as it will get.

 

[xcr440]

If you want the vlaves to open faster or slower change the springs. There are many combinations out there. I tried it on my 700 and ended up back to stock. The valves either opened too fast or not enough for stock applications.

 

[BarkMulcher]

Isn't this part of being a Fanatic[] I don't want to tinker with them, just want to think I know how too...
I already screwed up my valves once...I'm not gonna touch them []

 

[radianguy]

Not to be a smart ass, but you are gonna have to touch them again. They need to be cleaned at least every 1000 miles. I clean mine at 500 mile intervals just to make it easier. I wouldn't be picking with them though just for the sake of picking, take them out to clean them and once a season take them apart for a good cleaning.

 

[xcr440]

This is polaris's explanation on how they work on a 97/98 xcr 440....
http://www.snowmobilefanatics.com/forum/topic.asp?TOPIC_ID=57726