About 3 weeks ago, my cousin found a really deep mud hole, and sunk his '04 WR450 in the mud. It was buried up to mid gas tank and took almost 3 hours to get out. I really wish I was there to see that, but then again, I probably would have been the first to go through the drainage tube instead of him. He got it home, and we tore it apart. We found mud throughout the carb, and in the head. We disassembled the whole top end of the engine, washed all the parts in a parts washer, and re-assembled. We triple checked the valve clearance, cleaned out the carb 3 times, and we are still getting a lean fire. The plug is turning white, the backfire popping is unbelievably loud, but the bike has plenty of power otherwise. My cousin is flipping out, saying he's just going to get a new bike... I'm thinking that we are really close to having it run again. Is there anything else anyone can think of that maybe we didn't think of? I hate to see my cousin blow 7500 bucks on a new bike, especially since this one isn't really in the best shape to sell. Any ideas would be appreciated.