Wrench & Repair

On side valve motors, it's easy to see how cam/valve timing and ignition timing work, and understand what's actually happening in the motor (with the heads off) What position the piston is in - Where the valves are on each cylinder, in relation to which cylinder is firing.  The Harley 45s are a great learning tool to educate a person how engines work, and what makes them work.  A mechanic has to understand how a motor works in order to correctly diagnose issues.  Myself, personally, after all this education, and thinking, etc . . . I still have a difficult time troubleshooting problems, which is the true test of a good Wrench.  You can be a great engine builder, a great machinist, etc., but a good Wrench is a difficult title to achieve.  It's probably the reason most of the oldest mechanics are the best Wrenches . . . they've seen it all and 'been doin' it the longest.