Place a sheet of cardboard against the wheel to keep oil off the brake or tire, place a suitable container under the fork leg and remove the drain plug which is a small hexagon-headed bolt at the rear of the fork lower leg, just above the wheel spindle.
Depress the forks several times to expel as much oil as possible, then repeat the process on the remaining leg. leave the machine for a few minutes to allow any residual oil to drain to the bottom, then pump the forks again to remove it.
Renewing their sealing washers if worn or damaged, refit and tighten the drain plugs to the specified torque wrench settings, where given, then remove the fork leg top plastic plugs; it may be necessary to remove the handlebar cover to gain adequate working space.
Unscrew the Allen screw filler plugs from the center of each fork top plug, using an open-ended spanner to hold the top plug, then lift the machine on to its center stand on level ground and wedge a block of wood or similar under the sump so that the front wheel is clear of the ground and the forks are fully extended.
Fill each leg with the specified amount of one of the recommended brands of oil (see Chapter 7 - Frame & Forks). Do not use ordinary fork oil; BMW forks are designed to work with oils of (approximately) SAE 3 viscosity. Most proprietary fork oils are up to 10 times thicker than this and will produce a very stiff ride. Check the oil level by inserting a length of wending rod 1 meter (40 in) long by 5 mm (0.2 in) diameter into the fork leg; ensure that the level is the same in both fork legs. Refit the filler plugs, tightening them to the specified torque wrench setting, where given, followed by the plastic top plugs and/or any other disturbed components. Push the machine off its stand, apply the front brake and pump the forks up and down 5 - 10 times until the damping effect can be felt to be fully restored.
Next Section: 5. Clean the speedometer impulse transmitter