They are certainly not as easy to remove as the props. I made them fit snugly around the motor shaft so that they would not wiggle from side to side. I didn't want them to put any tension on the delicate plastic parts they cover. You should be able to hold the motor with one hand and use the other to push, turn, and slide the motor cap up and off of the motor shaft.
If you try them again and still do not like them, email me at
[email protected] and I'll send you a new set. I can sand the hole in the middle a bit to make them easier to slide off.