In 2011, BMW introduced the world's only production inline-six motorcycle engine: the 1,649cc K1600. It was not an incremental improvement on the Flying Brick — it was a completely new architecture, designed from scratch to be the widest-touring motorcycle BMW had ever built, while remaining narrow enough to lane-split.
An inline-six has a fundamental engineering advantage: perfect primary and secondary balance.
At any rpm, the firing intervals are equal (every 120° of crankshaft rotation), and the opposing
pistons cancel each other's vibration completely. The result is an engine that runs with
the smoothness of an electric motor while producing the sound of a racing machine.
BMW's K1600 inline-six displaces 1,649cc across six cylinders — 274.8cc per pot.
At just 55mm wide (narrower than a four-cylinder sportbike), the engine fits
within a touring motorcycle's frame without requiring wide saddlebag clearance.
The K1600GT produces 160 hp and 175 Nm of torque — usable from
1,500 rpm. At highway speeds, the engine turns at just 3,500 rpm, barely above idle,
leaving an enormous reserve of power available at any moment.
The K1600 Grand America (2017) takes the concept further: a full-dress touring bike
with a 30-litre top case, heated rider and passenger seats, adaptive LED headlights,
and a semi-active suspension system updated from the K1300S's ESA.
