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A buddy of mine that rides a raptor told me thats the new big thing on his website. A one way valve on his crankcase breather hose. A check valve which lets air out (pressure) and no dirty air back in. The guys that have them say they can tell a diff. - quicker throttle responce, smoother acceleration, etc... They even dynoed the product and it made right at 1.5 hp more. Has anybody else heard about this or is already running one??? Let me know... It is from a guy named Kenny on the raptor 700 forum that has his own shop.
 

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It is a PCV valve and I've seen them (on the net videos... not in person) on a KTM dirt bike. They too claim to make more power, but I can't under stand how.
 

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this is true.... If you can evacuate the bottom end crankcase pressure, the engine will rev faster and develop more power.

I'd be interested in connecting a valve to the exhaust so the low pressure in the exhaust can 'yank' on the case pressure (so to speak)...


there is a center case gasket modification that helps relieve crank case pressure too.... :D
 

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Same idea as the PCV valve, but much more reliable and more sensitive. I have seen a 2hp gain on top on a Yfz, have not tried one on a Trx
 

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I guess I don't see how a check ball is evacuating crank case pressure? I understand all about relieving crank case pressure to rev higher, faster, and cleaner, but I don't understand how a check valve with a ball in it is doing anything other then allowing pressure out and no return pressure back in (as the ball closes off the opening).

Maybe some one has a picture or something to help with this for me, as far as what and how it works.
 

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"a scavenger system with venturi tube on the exhaust to draw out combustion gases and maintain a small amount of vacuum in the crankcase to prevent oil leaks on to the race track is completely different than a PCV...

either choice, a PCV or exhaust crankcase venturi tube, still requires relief in the center case gasket.... center case gasket emissions passage is the main governing factor on how much can be evacuated from the bottom end....

honda's emissions passage in the centercase gasket is small enough IMO to be considered the 'choke',... LOL!
 

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I do believe honda has thought of this already... they have a one way valve below the crank to let the pressure out during the downward stroke... but doesnt let the air back in on the up cycle...
 

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This stuff is as old as the hills

VAC-U-PAN
Highly effective method of achieving optimum power through significantly reducing internal pressures. Breather of the unit attaches to valve cover and probe is inserted into header. Exhaust scavenging pulls pressure and blow- by out of motor.
 
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