Powerband

The powerband is the range of engine speed where the engine produces strong, usable power, roughly from where torque starts to rise to just past peak power. Below it the engine feels flat; above it power falls away.

Engines differ widely. Racing two-strokes have a narrow, sudden powerband because the expansion chamber only works well in a limited rev range, hence the slang “on the pipe”. Big four-stroke twins and touring engines have a wide, flat one, pulling from low revs.

The gearbox exists to keep the engine in its powerband. A rev counter, gearing choice and, on two-strokes, exhaust power valves all help. If a bike feels slow, check whether you are riding below its powerband before blaming the engine.