so i crashed my 5inch pretty hard last week, front left arm took most of it and the motor was obviously toast, bell was cracked and one of the magnets had actually chipped. got a replacement motor, same spec as the others (2306 2450kv), bolted it on and now thats all she wrote ? massive vibration through the whole frame when i throttle up past like 40%.

i went back and checked the mount screws, all tight, props are balanced, tried two different props just to rule that out. rpm filtering in betaflight is set the same as before the crash. i honestly cant figure out what im looking for at this point. gyro traces look a little rough on that motor channel but im not super confident reading the blackbox data to know if thats actually the problem or just a symptom of something else.

did i get a dud motor or is there something about reinstalling that i probably did wrong? feels like ive done this before without issues but this one is stubborn.

check the motor screws going into the bell, not just the mount screws. if one of those is even slightly loose or crossthreaded it'll throw the whole thing out of balance under load and you wont feel it with your fingers at rest. also worth checking if the arm itself got bent from the crash ? even a tiny deformation in the carbon can change the motor alignment enough to cause vibration. ive seen arms that looked totally fine visually but were actually slightly twisted. run your fingers along the underside and see if it feels flat.

if none of that, run the motor test in betaflight and listen for any inconsistency in the tone as it spins up. a dud motor will usually sound slightly rough or have a wobble you can feel with two fingers on the bell.

had almost the exact same thing happen after a crash, turned out the arm had a hairline crack i didnt see and it was flexing under throttle. wasnt obvious at all until i held a light behind it. might be worth a close look at that before assuming the motor is bad.