Changing the code to run faster - direct port manipulation HELP!

Hi Robin2,
If I leave the rest and just replace with this code works but I have not faster.
Work this code

void loop() {
  //do stuff dependent on encoder position here
  //such as move a stepper motor to match encoder position
  //if you want to make it 1:1 ensure the encoder res matches the motor res by dividing/multiplying
  if (encoder > 0) {
    digitalWrite(motor_direction, HIGH);// move stepper in reverse
    digitalWrite(motor_step, HIGH);
    digitalWrite(motor_step, LOW);
    delayMicroseconds(600); //_delay_us(200); //modify to alter speed
    motor_position++;
    encoder = 0; //encoder--;
  }
  else if (encoder < 0) {
    digitalWrite (motor_direction, LOW); //move stepper forward
    digitalWrite (motor_step, HIGH);
    digitalWrite (motor_step, LOW);
    delayMicroseconds(600); //_delay_us(200); //modify to alter speed
    motor_position--;
    encoder = 0; //encoder++;
  }
}

This not work

void loop() {
  //do stuff dependent on encoder position here
  //such as move a stepper motor to match encoder position
  //if you want to make it 1:1 ensure the encoder res matches the motor res by dividing/multiplying
  if (encoder > 0) {

    //digitalWrite(motor_direction, HIGH);// move stepper in reverse
    PORTD = PORTD | 0b00100000;
    //digitalWrite(motor_step, HIGH);
    PORTD = PORTD | 0b00010000;
    //digitalWrite(motor_step, LOW);
    PORTD = PORTD & 0b11101111;
    delayMicroseconds(600); //_delay_us(200); //modify to alter speed
    motor_position++;
    encoder = 0; //encoder--;
  }
  else if (encoder < 0) {
    //digitalWrite (motor_direction, LOW); //move stepper forward
    PORTD = PORTD & 0b11011111; 
    //digitalWrite (motor_step, HIGH);
    PORTD = PORTD | 0b00010000;
    //digitalWrite (motor_step, LOW);
    PORTD = PORTD & 0b11101111;
    delayMicroseconds(600); //_delay_us(200); //modify to alter speed
    motor_position--;
    encoder = 0; //encoder++;
  }
}