so i binned my 5inch pretty hard into a tree last week and ever since then motor 3 has been doing this weird twitchy thing on spinup. like it'll hesitate for half a second then kind of jerk into the right direction. the other three are totally smooth. ive already reseoldered the motor leads to the esc because one of the pads looked a bit cold but it didnt fix anything.

the weird thing is if i just plug in and dont arm, i can manually spin it in betaflight motor tab and it seems okay at very low throttle but once i push it past like 20% it starts hunting and shuddering. temps on that esc seem fine after a bench run, no hot spots i can feel. im using aikon 45amp 4in1 btw.

anyone had this before and figured out which component was actually dead? i dont really want to drop on a new stack if its just a $12 motor thats got a bent shaft or something messed up internally

had almost the exact same thing last year. nine times out of ten when its twitchy like that after a hit its either a bent shaft causing vibration feedback that confuses the esc, or one of the motor phases is partially shorted internally. easiest way to check is just swap a known good motor onto that esc and see if the behavior follows the motor or stays on that arm. if the replacement motor runs clean then yeah youre buying a motor. if it still twitches with a fresh motor then something in that esc channel is toast.

also worth checking the motor screws, ive had a loose mount cause similar symptoms because the whole thing was just vibrating loose on the arm and messing with the signal.

could also be the motor bell got slightly warped or the magnets cracked inside. had a 2306 that looked fine externally but one magnet had a hairline fracture and it did exactly what you're describing. you could feel a slight rough spot when you spun the shaft by hand. def swap the motor first before assuming its the esc, way cheaper to rule out