Part 3 - The crankshaft - basics

The Crankshaft

 

The crankshaft is a rotating assmebly that converts the up and down motion of the piston into rotational motion, that drives the rear wheel and gets you on your way. If you want to be technical a crankshaft converts liner motion into rotation motion around a fixed axis. The crankshaft has an offset CRANKPIN and a main rotational axis which the crankshaft spins. The crankshaft is divided into 3 sections, the main shaft (1), the crank throws (2) and the crank pin (3).

 

 

The main shaft runs through the center of the crank and is the main axis which the crank rotates around. The crank throws extend the crank out so a pin can be housed off-center. The crank pin attaches the two halves together and links the CONNECTING ROD in place. It should be pretty obvious how a cranksahft works, so I won’t bother explaining. We’ll onto the connecting rod abit later. 

The crankshaft is a press fit crankshaft, i.e the two halves are pressed onto the crnak pin with great pressure, this has been highlighted in blue. It’s friction that holds the two halves and the pin together. This is some times called a Friction Fit, for obvious reasons. On one side of the crank the Variator Assembly is fitted and the ignition/charging system is fitted to the other side, but more on that later.