It is a very poor idea to use delay() in a program where a quick response is essential because it blocks the Arduino until it completes. Use millis() to manage timing as illustrated in Several Things at a Time.
Have a look at Using millis() for timing. A beginners guide if you need more explanation.
For a project such as yours it would be a good idea to send a message at regular intervals (say 5 or 10 times per second) even if the data does not change. Then if a few messages fail to arrive the receiver will know there is a communication failure and can turn off the motor.
...R