To get power out of the engine, a series of reduction gears are used in a variety of ratios--five are used, to be somewhat exact. They slide and mesh and intermingle with each other in a selective dance designed to allow the engine to always operate at its most efficient.
I think the ancient Chinese first used a wooden form of "gear" in a toy (something like the 27th century BC, and in the 4th century BC Aristotle described them) that evolved and refined into hardened, precision ground steel and 98% efficiency.
Honda's version is smooth but I think the previous owner was a bit of a hot rodder and jammed the transmission into gear, hard, and bent a shift fork. In its turn, the gear that fork moved did not engage its mate properly. So under power, it jumped in, then out, then in, repeatedly, until the engagement pawls rounded.
They're the shiny worn portions in the picture: ugh and double ugh.
The work never ends.
The good news is: rummaging around in my boxes of spares, I had them all! So five hours of a Saturday later, I'm back to 62mpg.
And, smiles all around.
