But if the motorcycle leans at an angle to the vertical to the wall then the normal reactions from the wall, will produce a tendency to rotate (a torque) in the opposite direction.
So if the rider leans the motorcycle at the correct angle then the torques will be equal and no rotation will occur.
For other angles of lean there will be unbalanced torques causing the motorcycle to rotate and fall.
At these other angles of lean the rider's muscles will need to push more strongly in order to supply the extra torque to maintain balance. The rider may also experience nausea (because the endolymph fluid in the ear will experience an unbalanced torque and rotate).
These three forces (friction forces on each of the tyres, a weight force through the centre of mass) balance but are not in the same line. Which means the motorcycle will tend to rotate and tip over.
The normal reactions from the wall (acting where the tyres touch the wall) cannot help to balance this torque because they will not produce any turning effect if the motorcycle is perpendicular to the wall: