Motors are usually easy to install into all Whoop frames. They stay in there nicely!
Sometimes too nicely..
If you are having trouble to remove motors from a frame without cracking the frame, you need a Mosquito Forceps! That is a cheap tool usually used in surgery to clamp tissue or blood vessels. It has a straight or curved tip that is shaped like a set of needle nose plier, and the handle has loops like a pair of scissors.
This tools is perfect to stick it into a little gap and then push the prongs apart.
On the Whoop frames, stick the tip between motor and frame, push apart, the the motor will come half-way out without stressing the frame or the prop.
When the progs pushed the motor as fas as the mount allows, turn the tool over and push the tip into the end of the motor to remove it completely.
I tried a few different shapes and sizes, and the 12.5" curved variety is my favourite.
Just google "12.5 curved mosquito forceps" and you will find plenty of them for cheap on ebay.
If you have friends working in a hospital, ask if they can bring some. Tools like this get thrown out in perfect condition when the sterilisation expires.