The up-down movement of an engine’s piston(s) is driven by the rotation of the crankshaft. In a conventional inline 4-cylinder engine, the outer and inner pistons have
the same up-down motion. Looking at the crankshaft from the side,
the pairs of pistons overlap at 180°. With a crossplane crankshaft,
the four crankpins are set at 90° intervals, producing torque with a shorter interval. This results in a clearer feeling
of torque from the engine. It also brings good response when cornering, etc.,
when finer throttle inputs are needed and delivers performance advantages with
sport bikes using high-revving engines in particular.