Yes, spring in to motor, which allows you to push in and adjust length while aligning and clearing the edge of KK opening. You may have to "pull it out just a bit once aligned"
You should not have to file anything. It should all fit together nicely.
Use the the square shaft on Basket to insert from the inside of KK into opening.
see pictures:
motor bracket installed and alignment
oops..turn the head a bit, see spring loaded square shaft in motor
"In the midst of a busy life, take some time to be a kid again." -- Fortune Cookie
Her name is Kahlan !