Bike is a WR426f. I had a rock flip up and hit the waterpump cover and blew a hole in it without me noticing. 10 minutes later the bike seized. After ordering a new wiseco piston kit and resleeving the jug, I thought I was back in business. I have a hotcams exhaust and after timing it up with all the marks and putting it back together, it fired right up. I didn't let it idle for more than 10 seconds because it was late and I was tired. But it sounded fine. The next day I fired it up and it sounds like the valves are slapping hard. Really noisy. It starts up fine though. I figure the timing chain is stretched so I got a new one and got it installed. The bike is a bitch to start now and it still noisy as hell. A leak down test confirmed my suspicions, I was losing air bad through the intake. So I tore it down and this is what I found: Valves have nicked the piston. Where is the dumfounding part of it. What the hell would cause the valve to nick the piston like it has? Notice the mark on the right side of the right exhaust valve and also a nick on the left side of the center intake. It looks almost like the valves are aligned with where they should be on the piston? Any ideas?