so i binned my 5inch pretty hard into a concrete barrier last week, props took the hit mostly but one of the motors has been making this faint grinding/scraping sound since then. not constant, kind of comes and goes depending on throttle input. its still spinning, doesnt sound like its going to seize up or anything but its definitely not right.

ran the motor test in betaflight and it spins up fine, no stuttering in the graph but you can just hear it. been flying it a bit more since then which was probably dumb but i wanted to see if it would work itself out. it hasnt.

my question is basically whether thats a bent shaft situation or if theres debris in the bell or what. i pulled the prop off and spun it by hand and there's definitely some resistance in one spot of the rotation, like a slight catch. i dont have another motor to swap in right now and i dont want to order one if maybe i just need to clean it out or something.

that catch you're feeling by hand is almost certainly a bent shaft. concrete hits are brutal for that, the bell takes the force and the shaft bends just enough to rub on the stator. cleaning it out won't fix that unfortunately. you can sometimes straighten a shaft with pliers and patience but honestly the results are pretty inconsistent and you're usually better off just swapping the motor before it gets worse or throws a prop mid flight.

what motors are you running? if theyre something common like xing or brotherhobby you can usually find singles pretty cheap rather than buying a pack of four.

ive had the exact same thing happen and yeah i tried to ride it out too lol. eventually it did seize mid flight and i dropped it from like 60 feet so. just replace the motor. the time you spend second guessing it isnt worth the risk of losing the whole quad over a 15 dollar motor