Curious to see what you guys think caused this. The bike ran great I was just going to re-ring it to get it ready for next season when I found this. The previous owner did a top-end before I bought it; I put 3 races on it and a few trail rides. Sorry for the somewhat blurry pictures the camera had trouble focusing. The rings look fine, just wondering when this could have happened. I figure I will need a new piston and re-plate. Any advice on where to go for either?