Six-cylinder engines are pretty rare in the world of bikes, obviously due to packaging issues. If installed inline, it would either be too wide or too long to fit a bike frame properly. So we see V6 and boxer formats for 6 cylinders in bikes more often than an inline installation. Honda has made both boxer-6 and inline-6 bike engines before, installed in the Goldwing and the CBX respectively.
Though the very popular 320i here has a four-pot, BMW cars are very much well-known for their silky smooth inline-6 engines. BMW is now trying to bring inline-6 into bikes in a big way, as according to them it is the packaging issues that have prevented the cylinder format from really going anywhere when installed in a bike, whether in a production model or in motorcycle racing.
BMW claims that the BMW Motorrad Concept 6’s inline-6 engine is approximately 10cm slimmer than any production inline-6 engine coming before it, and it is only a bit wider than a large-capacity inline-4 engine with conventional technology. BMW has used a slightly over-square bore to stroke ratio measurement with a relatively long stroke and small gaps between cylinders. Electrical ancillaries and drive components are situated behind the crank in the open space above the transmission in order to minimize width.
The engine’s construction uses lightweight materials in as many areas as possible in order to keep the engine relatively light. Some weight-reduction techniques include hollow-drilled camshafts and light conrods. The engine’s inline-6 configuration does not require the use of a balance shaft. The block uses dry sump lubrication, helping lower the engine installation position. Like inline-4 installed in the BMW K 1300 series, the engine is tilted forward by 55 degrees for a lower center of gravity and better weight balance. The tilt angle also allows extra space for the aerodynamically-positioned intake manifold.
And now for some numbers. The inline-6 has 1.6 litres of displacement and can produce 130Nm of torque from just 2,000rpm. It revs up to nearly 9,000rpm. Look after the jump for photos of the Concept 6.
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