Up until 2006, BMW’s motorcycle range comprised the 1,200cc boxer twins and four-cylinder engines, with the single-cylinder 650 range, and nothing in between. In an attempt to expand its range, the Bavarian firm released the F800 range – powered by a parallel twin-cylinder engine that offered strong middleweight performance. The F800 engine is marked out by a unique balancing system. The top end of the engine is largely conventional, with four-valves per cylinder, fuel injection, and twin camshafts. But the bottom end is unique. BMW engineers have mounted a long, weighted bar on a pivot at the back of the engine, which then connects at the front to the crankshaft via a small con-rod. As the crankshaft turns, the weighted bar pivots up and down, and this movement cancels out the movements of the pistons, balancing these forces and reducing vibration.
This innovative engine is fitted into a more conventional chassis design, with a twin-spar aluminium frame and sporty running gear. This ST version of the F800 has a full fairing to keep the rider out of the weather, and with optional panniers, it makes an effective, sporty, light tourer.
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