this may be a stupid question considering I'm a two stroke rider. I know how to change one put it back on in top end jobs all that jazz but what exactly is the powervalve like what is it's function? I know it opens at a certain rpm and gives you a major boost but what is it introducing more air/gas or what?
It kinda does the same thing, if you would run a small carb on your bike. It would give you more low end, but it would take away topend, because the flow can only move so much air. So when closed, it restricts the flow. (It also changes the sound waves, but that is more indepth) Too much air in a motor, when it is at low RPMs can work against you. So when you close that power valve at low RPMs, it limits the air flow, but when it opens up, with RPM or electronic valves, it starts flowing more air, thus the rise in HP at that point. Try running a 40mm carb on a 125. It will have 0 bottom, but if the motor can accept the 40mm flow at top end, that thing will sing. On the big bore motor, apples to apples like a 500AF vs 450F, you don't need it so much, because the torque of the 2 stroke will still give you enough low end to beat the 450F anywhere in the curve. One thing to keep in mind on the big 500AF's, is that they use the same carb as the 125's now a days. 38mm. HP would be out of this world with a matching carb, unless you believe a 500 breaths the same as the 125s do. I'll compare 250 2 strokes to 250 4 chokes instead of skewing things, because the people who keep on saying how great the 4 strokes are, always bring up how great the 450F is, blacking out the 250F as if it doesn't exist, like the media does Ron Paul. Even though as amateurs, we run cc vs cc mostly.
