You are dividing down the input signal voltage to the LM3914 but then its input is close to its comparators input offset voltages. It would be better to increase the reference voltage by connecting two series resistors from pin 7 to ground and connecting pin 8 to the junction of the resistors, similar to the LM317. Then the resistor ladder feeding the comparators in the LM3914 have much higher input voltages. The two resistors control the LED current and brightness. Then maybe the entire output voltage of the LM317 can feed SIN IN on the LM3914.
Again, your new LM317 has a minimum output voltage of 1.2V which is too low and since R LO pin4 on the LM3914 is at 0V then the bottom few LEDs will light when the motors are not running at the very low voltages.
Pin 4 needs a resistor to ground to increase the required minimum input voltage that will light the lower LEDs. But you do not know the voltage when the motors will start running since you are not using Pulse Width Modulation.