Unlike RC cars, RC bikes have no direct linkage. This is due to the fact that between cornering speed and lean angle, there is always an appropriate amount of steering free play to allow the forks to adjust and achieve balance. A rigid linkage between the servo and triple tree cannot achieve this.
What exactly happens when cornering?
To get a motorcycle leaning to the left in the curve, it is a small steering pulse to the right to initiate the left turn. First, the bike is actually running minimal right, before the balance of the bike is shifted to the left, resulting in the bike leaning into the corner and then the front wheel follows its path.
This means for an RC Bike, steering must be set in reverse on your radio controller, that is, a left turn input on the Transmitter causes a movement of the forks and front wheel to the right.
The bike therefore leans into the corner and the contact force of the front wheel along with the trail in the geometry generate a steering torque.
This torque counteracts a restoring torque which is produced, by the force of the steering spring and its lever arm to the steering axis. It is essential to ensure smooth running in the steering head bearings.
Even minimal friction will affect driving behavior noticeably. To check the performance of head bearings, remove the damper linkage to the forks and pivot the fork slowly back and forth. This must be completely smooth as possible, any binding of the fork bearings and or steering head shaft must be checked and possibly replaced if necessary as part of a routine maintenance schedule.