been chasing this for like three days now and its driving me insane. one of my rear motors stutters and hesitates on throttle up, not all the time but enough to be super noticeable in the logs. it was fine and then after a pretty rough landing in tall grass i noticed it starting. no visible damage anywhere.

i already reflowed the solder on all three motor phase wires because one of them looked a bit cold. still doing it. swapped the motor to a different ESC channel just to rule out the motor itself and the stutter followed the motor, so its definitely the motor. but visually it looks totally fine, spins freely by hand, no grinding, magnets feel normal.

is there something inside the motor i should be looking for that wouldnt be obvious from the outside? could grass or dirt in the stator windings cause this kind of thing? i dont really want to buy a new motor if i dont have to but also im aware im probably just delaying the inevitable here

grass in the stator gap can absolutely do this, ive seen it wreck motors slowly over time rather than all at once. get a can of compressed air and blast it through from every angle, then spin it by hand again. sometimes you can actually feel a tiny bit of resistance in one spot of the rotation if theres debris or if a winding is starting to fail. if it still stutters after cleaning id check the motor screws too, a loose motor mount can cause all kinds of weird vibrational issues that look like motor stuttering in blackbox but arent actually the motor windings at all.

that said if youve already confirmed the stutter follows the motor across ESC channels thats pretty damning. could also be a partial winding short from the impact, which you basically cant fix without rewinding and at that point just get a new motor.

yeah i had something simlar, turned out one of the tiny bearing retaining clips had shifted slightly after a crash. motor spun fine by hand but under load at higher RPM it was causing a wobble inside. couldnt see it at all until i actually pulled the bell off and looked at the bearings directly. might be worth popping the bell if you havent already, takes like two minutes