Road test: 2005 BMW R1200GS

But the big news out of the BMW camp is the fitment of a balance shaft, a first for the Boxer engine. A flat- or opposed-Twin like BMW's Boxer motor has perfect primary balance, much like a 90-degree V-Twin. But secondary forces from the engine's rotational mass, called a rocking couple, causes unwanted vibration the creep through to the rider. BMW's use of a counterbalancer reduces this effect, making for increased comfort for the rider and less stresses on reciprocating engine components, also allowing for a higher redline.