Fit the hexagon wrench (D) into the hexagonal part of the body (C) and the wrench (E) onto the bolt.
Turn clockwise the bolt (F) until the pin comes out.
Remove the chain.
Engage a low gear and unscrew the nut (3).
Remove the nut (3) and the lockwasher (4) on the sprocket.
Remove the front sprocket (5) from the gearbox secondary shaft.