To complete one operating cycle, how far must the crankshaft of a 4-stroke engine rotate?

In a four-stroke engine, the operating cycle consists of four distinct strokes: intake, compression, power, and exhaust. Each of these strokes corresponds to specific movements of the crankshaft.

Throughout this operating cycle, the crankshaft needs to rotate completely twice – covering a full 720 degrees of rotation. This is because, in a four-stroke engine, one full cycle requires the piston to move down and up twice: once for the intake and compression strokes, and again for the power and exhaust strokes.

Therefore, to complete the full operating cycle from the start of the intake stroke to the end of the exhaust stroke, the crankshaft rotates a full 720 degrees. This amount of rotation effectively allows the engine to complete all four processes essential for internal combustion to occur, which is why this option is the correct answer.