Redline

The redline is the highest engine speed the manufacturer considers safe, shown as a red zone on the tachometer. Above it, valve springs, pistons and connecting rods face loads they are not designed for. Most modern bikes have a rev limiter that cuts ignition or fuel at or near the redline.

Redlines vary widely: a large twin may stop around 8000–9000 rpm, while a 600 cc four-cylinder sports bike can rev well beyond 14,000 rpm.

Maximum power is usually reached a little below the redline, so bouncing off the limiter rarely makes you faster. During running-in and on a cold engine, stay well below it.