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BMW developing bike size six-cylinder engine

By Matt Brogan |

The straight-six is undeniably one of the most successful engine configurations in motoring history.

Think Mercedes-Benz, BMW, Jaguar, and here in Australia, Ford, and some years back, Valiant and Holden.

And while it has always been the dream of engineers to transplant the technology into bikes, it is something that few customers have ever warmed to.

concept 6

The biggest issues with six-cylinder units have always been weight and size, off-setting any power advantages and disturbing weight distribution and centre of gravity.

But BMW Motorrad is having another go at it with the new Concept 6, technology that is set to make its way into the K-Series in the not too distant future.

concept 6 2

BMW claims the engine is approximately 100 mm slimmer than all former straight-six production engines and only a bit wider than a large-capacity straight-four with conventional technology.

The reduction in width is achieved by the slightly over-square bore-stroke ratio with relatively long stroke and very small gaps between cylinders. To achieve the compact configuration the electrical ancillaries and their drive components are positioned behind the crankshaft in the open space above the transmission.

The two hollow-drilled camshafts and light connecting rods help to keep the weight down.

concept 6 1

The straight-six featured in the Concept 6 follows the straight-four in the K 1300 model series, again coming with cylinders tilted to the front by 55-degrees.

The engine features with dry sump lubrication leading to greater reliability under extreme conditions and meaning the engine can be positioned lower than on a conventional layout.

Power output will be about the same as BMW’s 1.3-litre straight-four power units, but torque is boosted to 130Nm and is available from 2000-9000rpm.

There is no word on fuel efficiency or emissions yet, but BMW says with a catalytic converter it is comparable to other four-cylinder units under touring conditions.

concept 6 4

The design – with its long front end and short rear – draws on the legendary Cafe Racer, created with the engine at the heart to visible from every angle.

The Concept 6 also scores 17-inch HP forged wheels and six-piston fixed callipers to add to the sporting look.

The instrument panel is minimalist in design, but replaces the conventional rev counter with an LED display which shows the rider how much torque is available whenever required.

by Tim Beissmann


 
  • bob

    Its not just the size and weight that have put people off. But also the complexity. The high tech 4′s are complex enough.

  • Reckless1

    Honda had the right idea years ago – the CX500 Turbo V twin.

    With the advancement of turbo technology since those days, a rebirth would be quite spectacular I reckon.

  • Mitch

    Seems strange that all auto makers are downsizing their engine and using forced induction yet BMW bikes are making bigger engines. Maybe forced induction doesnt work on bikes.

    • Lorrie

      Well a bike generally gets great fuel economy anyways.

      • Simon

        That depends on how it’s riden!

    • Alan

      They are not making bigger engines though, it has the same 1.3L as the current BMW K-series engine, just with two added cylinders.

  • Lorrie

    Wow, this is a really nice looking bike. I really dont know much about bikes to be honest but this is something I can get into. The small touches like the \\\ exhaust pipe

  • Simon

    A company in Sydney does a turbo mod to the Hyabussa. It’s truly scary how fast it is. For the weight of a turbo and intercooler, I’m not sure 6 cylinders is the way forward.
    Triumph have a 2.3L 3 cylinder. So there will always be “bigger than yours”.

  • Jeremy

    Hmmm… love the BMW motorbikes (especially the K1200R/K1300R), but they’re a bit slow on the uptake. Always loved inline-six motors, and the late 70′s Honda CBX-1000 always piqued my interest. Haven’t been able to find one for sale though.

  • person

    The Benelli 750 Sei is a motorcycle that was produced by Italian manufacturer Benelli from 1972–1978. It was the first production motorcycle with a 6-cylinder engine.[1] The engine was based on the four-cylinder Honda CB500, but with two extra cylinders. The cylinder head fins of the Sei were squared off to provide a cosmetic individuality; but otherwise the engine is in most respects obviously derived from the Honda.

    Despite the extra cylinders, the Sei’s width was kept to a minimum by siting the alternator (which, on the Honda, is at the left-hand end of the crankshaft) behind the cylinders. Cooling was improved by having air passages between the cylinders. The Sei had three carburetters, compared to the Honda’s four. After four years of production, Benelli developed the 750 Sei into a 900cc motorcycle, with six-into-two exhausts.

    I rode one.

  • Karl

    Waste of time. with engine mapping technology these days, a compact turbo with 2 or 3 cylinders is the go. the smoothness and torque of the old BMW k75 engine with some stonking big turbo hanging off it would have no peer, especially with todays ecu’s and general engineering.

  • Yanzo

    yeah when i saw this bike i was immediatlly like damn, if i get a bike i want this one

  • http://carz.com/ Carz

    I’m not actually into bikes but this BMW is definitely something. And yes, if I do buy a bike someday, this is definitely it.

  • Robin Graves

    Turbo’s dont work too well with bikes. Lag is the main issue, and packaging in all the extra plumbing and intercooler etc. Kawasaki had a fairly successful Z1300 that was an inline 6. http://en.wikipedia.org/wiki/Kawasaki_1300 I remember seeing a bike magazine cover years ago with a guy doing a burnout on a Z1300, standing on the pegs doing a donut, with a full-leg plaster cast! Classic.

  • AAA

    BMW’s marketing excercise than anything else ~

    • Robin Graves

      Just the sound of a six cylinder makes it a worthwhile venture. Listen to the Honda 6 cyl Valyrie its sounds fantastic.

  • http://www.CarZ.com CarZ

    Honda’s where it’s at. They’ve got the players hand on motorbikes. but hey, maybe this will be greater than it appears. I can’t see this having much power though.

  • Baddass

    Power figures CA?