912ul valve sticking.

Sorry for delay in responding to your comments. Work got in the way...

As mentioned previous, I had the carbs pulled. I disassembled, cleaned and reassembled both carbs. Used a carb mate to balance and the motor is running very smooth.

I did notice on full throttle take off the RPM only reached 4900, although it came up to 5200 max during full throttle flight (engine warmer). I know the prop pitch is set a little course howerever i can usually get 5600  at full throttle. I will do a compression check on the motor. Any thoughts?