Using a high flash-point solvent, wash the upper and lower ball bearings in the cages, and wipe the upper and lower outer races, which are press-fitted into the frame head pipe, clean off grease and dirt.
Visually check the outer races and the ball bearings.
Replace the bearing assemblies if they show wear or damage.
Pack the upper and lower ball bearings [A] in the cages with grease, and apply a light coat of grease to the upper and lower outer races.
Install the steering stem, and adjust the steering.