Displacement is the measure of the total volume of all engine cylinders. Ever wonder how to figure it out? This is for those who are curious, but geometrically-challenged.

To show how the equation works, we'll use the H22 as an example. Keep in mind: π ≈ 3.1415926535897932384626433832795

Displacement = (87mm ÷ 2)² × π × 90.7mm × 4 cylinders

Displacement = (43.5mm)² × π × 90.7mm × 4 cylinders

Displacement = 1892.25mm² × π × 90.7mm × 4 cylinders

Displacement = 2156729.4319084178534884839225615mm³ (divide by 1000 because there are 1000mm³ in 1cm³)

Displacement = 2156.7294319084178534884839225615cm³ (round up to the nearest whole cm³)

Displacement = 2157cm³ or 2157cc

To show how quickly displacement increases, consider boring your cylinder by 0.25mm for oversized pistons. You've just increased your displacement from 2157cc to 2169cc.