| abstract | - Most inline-three engines employ a crank angle of 120°, and are thus rotationally balanced; however, since the three cylinders are offset from each other, the firing of the end cylinders induces a rocking motion from end to end, since there is no opposing cylinder moving in the opposite direction as in a rotationally balanced straight-six engine. The use of a balance shaft in an antiphase to that vibration produces a smoothly running engine. An exception to the 120° crankshaft can be found in some of the inline-three engines made by motorcycle manufacturer Laverda. In these engines (sometimes referred to as 180° triples), the outer pistons rise and fall together like a 360° straight-two engine. The inner cylinder is offset 180° from the outer cylinders. In these engines, cylinder #1 fires, then 180° later cylinder #2 fires, and then 180° later cylinder #3 fires. There is no power stroke on the final 180° of rotation.
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