Noises are notoriously difficult to diagnose, via videos or recordings. Check the stator rotor housing for vibration/noise, if memory serves me you used pattern parts when you replaced it, these can fail. The noise sounds like very similar to the high pitched wine bearings make when they spin in a rebate or spin on a shaft, it's also possible it's a lay shaft bearing, in the box, clutch or water pump drive.
It could be any number of possibilities, but start with what you've replaced, worked on or you know has been worked on and go from there. These engines are normally (other than the rotors) pretty reliable, what fails in my experience is owners fitting aftermarket tuning or pattern parts.