expected primary-expression before ')' token

Can anybody help me??

if(angle_gyro > 30 || angle_gyro < -30 || start == 0 || ){    //If the robot tips over or the startvariable is zero or the battery is empty
    pid_output = 0;                                                         //Set the PID controller output to 0 so the motors stop moving
    pid_i_mem = 0;                                                          //Reset the I-controller memory
    start = 0;                                                              //Set the start variable to 0
    self_balance_pid_setpoint = 0;
C:\Users\itallo\Desktop\Balancing_robot\Balancing_robot.ino: In function 'void loop()':

Balancing_robot:174:59: error: expected primary-expression before ')' token

   if(angle_gyro > 30 || angle_gyro < -30 || start == 1 || ){    //If the robot tips over or the start variable is zero or the battery is empty

                                                           ^

exit status 1
expected primary-expression before ')' token

angle_gyro > 30 OR angle_gyro < -30 OR start == 0 OR or what exactly? )

if(angle_gyro > 30 || angle_gyro < -30 || start == 0 || )

If the angle is greater than 30 or the angle is less than -30 or start equals 0 or, do something.

Or what?

(deleted)

it worked, thanks!!!