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To Power Valve Or Not To Power Valve?


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Are power valves really a good thing. I read this article and from what it said is sounds like it just helps smooth out the powerband and make more useable power. And on this chart thing it showed that the power valved motor had less peak hp than the non power valve motor.

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When displacenent is limited by rules such as with 125 and 250cc motocross bikes power valves will provide some bottom end while still allowing the motor to have all the top end you need. When displacement is not limited by rules such as with the Banshee or with certain vet and old timer MX classes power improvements are much more effective by increasing bore or stroke with appropriate carb, compression, porting, and timing. I think power valves on a Banshee can only be justified if you want something different and don't mind paying much more and getting much less. :(

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That's really going to depend on what you want the end result to be. If you're looking for a drag motor, powervalves may not befefit you much. If you're looking for a motor that can do more than one thing, they will help. When a powervalve is closed it's going to offer up more torque, yet when it opens the exhaust port is raised creating all the top end it was ported for.

 

I myself, for my kind of riding can not think of any drawbacks to them. Although there has been alot of debate about the time it takes for the powervalves to open, decreasing how fast the motor can rev up. The next question would be how do I want to add them to my bike. Cheetah, T-Rex, RZ, etc.

 

What exactly does this mean?

i would rather build a mean stroker/ drag ported beast for the price of powervalve cylinders. but thats just me wishing i had a bike to ride

 

Why not build a stroker/drag ported "PV Motor"? The monoblocks sure are alot easier to turn into a "big" stroker than a stock jugged bike. And if your going to go the monoblock route, why not get the powervalves? Maybe I'm just looking at this a different way.

 

Can you explain this a little furthure to me?

I think power valves on a Banshee can only be justified if you want something different and don't mind paying much more and getting much less.

 

I must just be misunderstanding what you're saying. I don't know where you would be getting less. If there is one thing everyone of us on here knows, the one place the Banshee lacks anything is low end.

 

I am speaking from experience seeing as I had a stock motor and turned it into a PV motor. I'm not disagreeing with any one, just may not understand exactly what you're saying.

 

 

broke

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Ok, so power valves give you more low end torque with out taking away from top end power.

I wasn't really talking about power valves for a banshee. I was wanting to know about a 85/100cc dirt bike.

 

I do alot of trail riding and drag racing and I have a few little race tracks. How would a KX 100 (what I am going to get if I dont buy a banshee) do for trails, motocross, and drag racing. It has power valves (they call it KIPS or something) so would it be a good choice?

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