Lack of a speed / distance reading is most often due to the speed sensor located on the Right front Fork being out of alignment. 

A possible related cause is that the wheel is reversed and the magnet is on the wrong side -- remove the wheel and turn it so the magnet is on the same side as the sensor.

Note the following image:

To remedy this situation, adjust the position of the sensor and / or magnet to align as shown in that image.