I checked my valves today and ran into a small issue: a big movement towards loose on one exhaust valve. Last time I checked them, at 20 they hadn't moved at all, which I was hoping would mean little to no movement up into the 50+ hour range. That held pretty true through 3 of 4 valves until I hit the last exhaust valve and to my shock could just fit a .28 feeler gauge through! I check my math, checked again and then decided to the turn the motor over a few more times and press on the bucket to be sure it hadn't been locked in place by oil friction. After that the .28 wouldn't fit any longer, but to my displeasure I could still fit a .26 gauge. Granted, this is only .01 out of spec, but the last two readings were .23 on the dot, so I'm a little perplexed as to how the other three valves are in spec and this one has jumped to loose by such a large margin. I'm guessing carbon build up, especially since the reading changed slightly after turning the motor over, but I'd love to here any other theories. A slightly bent valve is possible I guess, but I ride off road and don't ring it out on the limiter. Just confused as after years of checking valves I've never had them get looser, or had a spring wear out, bucket wear through, etc. Especially after so few hours. And, if you agree it's carbon build up, any thoughts around what I can do to loosen them from the valve/seat (fuel additive, high heat, etc.)? I can take it all apart if need be, but I'm hoping that won't be necessary as I hadn't planned on cracking it open until 50-75 based on compression and how the motor felt/started. Oh, and FYI the fuel has been rich-end at the bottom and the ignition has been retarded a bit to help ease the hit at first crack of the throttle. Come on Grey, give me some love on this one.