Bore and Stroke Calculator

Stroke-to-bore ratio, displacement per cylinder and total: square, oversquare or undersquare engine.

Formula

Displacement = (π/4) × Bore (mm)² × Stroke (mm) × Number of cylinders / 1000

Assumptions

Stroke-to-bore ratio, displacement per cylinder and total: square, oversquare or undersquare engine.

How to read it

Stroke/bore ratio < 1: oversquare engine, revs high; = 1: square; > 1: undersquare (long stroke), more low-end torque and better efficiency. At equal displacement, geometry sets the engine’s character.

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