Place the helicopter in the horizontal level, make its head face the pilot and assure the rotor grips is vertical to the tail boom. Keep the main rotor blades stretched in line, and assure the main rotor blades are parallel to the tail boom. Then use two index fingers to horizontally lift the rotor grips of helicopter.
If the head of helicopter goes down, it means the CG is too close to the foreside. Please move the battery pack a little backward. If the tail boom goes down, it means the CG is too close to rear end. Please move the battery pack a little forward