" Not everyone understands what a completely rational process this is, this maintenance of a motorcycle. They think it's some kind of " knack" or some kind of " affinity for machines" in operation. They are right, but the knack is almost purely a process of reason, and most of the troubles are caused by what old time radio men called a " short between the earphones," failures to use the head properly. A motorcycle functions entirely in accordance with the laws of reason, and a study of the art of motorcycle maintenance is really a miniature study of the art of rationality itself. "