I installed the RK Tek drop in dual ringers a little less than 600 miles ago in my '06 X Power Tek. 440 main jets, V-Force 3 reeds. Since new I have had no problems with them, until Saturday. I was making a climb @ WOT when she broke loose. Pulled the pto side plug and had 10 pounds of compression. Pulled the head and this is what I found. I was only 4-5 miles away from the trailer where I had just changed out my BR9ECS plugs and put in two new Denso W27ESR-U plugs. As you can see from the pictures, the outside of the piston appears like it melted, but the pic from inside the piston skirt looks more like a break. This is all on the front of the engine where the exhaust port is. Also, the top of the piston and head have tiny marks on them. Is this from detonation or from the pin that keeps the ring from turning breaking loose and getting on top? I would appreciate everyone's opinion so I can fix the problem so this doesn't happen again. Also, would you split the crank case and check for pieces of piston, or clean it out good from the top and put it back together? Thanks