I just wanted to give everyone an update. I've been using roll pins on my power valves for about 30 hours now. I took the bike apart today to put a new ring on the piston. The pins are working perfectly, no movement what so ever. The bike has been running perfect since I put them in. This is a good alternative for those that don't want to shell out the $150 plus each power valve costs from Yamaha. They can be difficult to press in, I used a bench vice and socket. I'll try to get to the hardware store sometime to check to see what size I used, but its obvious if you take one of your pins with you and match it up.