I've had alot of problems with my powervalve lately on my KX500, and I'm starting to get tired of it. The actuating arm has some gears on the inside which open and close the powervalve. Some of the parts are worn or not working properly I'm assuming, but it isn't opening the powervalve, and it is making my bike VERY slow at high rpm's. I miss my massive neon green powerband and it's now starting to feel like a four stoke. (No offense to you thumper guys) Anyway I've heard you can rig the powervalve open so it never closes. I've heard of people doing it on some of the smaller bikes. I was thinking of taking off the cylinder and setting up the powervalve so it is open and when I put it back together I wasn't going to attach the exhaust advancer which pulls the actuating arm in and out. Then the P.V. will always stay open. I was just wondering what type of effects this would have on my bike. I've been told that I will lose some of my bottom end but it will make the powerband hit more severe. I was hoping to get some feedback before I made a decision. Sorry for the long post. THANKS