BMW's Three Cylinder Future !

Recent patent documents point to a new engine configuration for BMW... could the Germans’ return to cruisers see something very different indeed ?

BMW Motorrad boss Stephan Schaller is on record as being determined to return his company to the cruiser market for the first time since 2004, when the German manufacturer ended production of the R1200C Boxer it had launched in 1997, of which it manufactured 40,218 units, including a smaller engine version – the R850C – which it phased out in 2000.

“ We don’t have a Cruiser right now– but we must indeed find the right answer to enter the biggest motorcycle segment of our largest export market, which is the USA,” said Schaller.

“However, we are definitely not going to do so by copying another brand, because this was never successful in the past. We must follow our own rules. If we did a V-Twin we definitely would do it differently, but we also have our BMW heritage [to consider], and perhaps that is a more important consideration.”

BMW Three Cylinder : Patently Obvious

Recent patent documents from the German manufacturer suggest a W3 engine format is likely to form the basis of such a BMW Cruiser range. Switching to a V-twin would be too much like copying everyone else – though it did this already in creating the inline four-cylinder S1000RR sportsbike range. But using a novel W3 engine layout would allow it to create a family of models unlike anything else in the marketplace.

So far, BMW has patented two variations of the W3 engine format. Both appear to be air-cooled, giving the clean, simple visual appeal necessary for a cruiser, and both feature pushrods instead of overhead cams – a decision in keeping with marketplace expectations, while also permitting a larger-capacity engine to be installed in a smaller space.

Compared to the Feuling W3, which had a 90º angle between the first and third cylinders, the BMW layouts feature a much tighter overall 75º format for the first design, and a 65º layout for the second one, with the patents showing both concepts as carrying a gear-driven balance shaft to help minimise vibration. These are much closer to a conventional V-twin cruiser engine’s dimensions, meaning a bike carrying the BMW W3 motor could follow traditional styling cues despite the extra cylinder.

Both BMW’s designs differ from the American W3’s master-and-slave crank layout in using more than one crankpin. One design has a triple-throw crankshaft that’s more like an inline triple, without any crankpin sharing. While this makes it wider than a V-twin, it still offers the all-important visual look, and allows the use of virtually any firing order or firing interval.

The second design features a layout that’s closer to a conventional V-twin cruiser engine format, with two cylinders sharing a single crankpin in normal V-twin mode, while the third piston gets its own crank throw, again allowing freedom with regard to firing interval. This design is narrower than the other, while still gaining the all important extra cylinder.

The iconic Boxer motor is key to BMW, and while it seems quite a leap to imagine the company adding another configuration to its flat twins, parallels and inline-fours, the patents make us more than a little curious. The recent unveiling of its Concept 101 bike showed a machine carrying the six-cylinder K1600 motor – something likely to become a "bagger" version of the K1600 : if BMW were to look at a new cruiser, we’d expect it to follow lines more similar to the R-nineT.

Riding A Radical BMW W3

BMW is a company that, on two wheels at least, is used to throwing off the blanket of convention that other manufacturers prefer to wrap themselves in. But its engineers often prefer someone else to have done the first R&D work, especially in terms of proof of concept.

The Telelever front end is really a copy of British engineer Nigel Hill’s Saxtrak front suspension design, which Hill regretfully omitted to patent, leaving BMW free to use it on its Boxer twins without fear of reprisal.

Likewise, the later Duolever front suspension of the four-cylinder K-models is a copy of the Fior fork invented by French designer Claude Fior back in the late 1970s, later adopted by British-based constructor Norman Hossack who did in fact patent it – though he ought not to have been allowed to, since Fior was there first three years earlier, but never registered the design. Hossack however failed to pay to maintain the patent, allowing BMW to pick it up free of charge for the first K1200S model.

So the news that BMW is working on a W3 engine highlights the fact that such a motor has existed before... The Feuling W3 was created in Southern California in the late 1990s, and several customer versions were made and sold before its creator, Jim Feuling, sadly passed away in 2002. Moto Guzzi also built a prototype W-layout motor 30 years ago, plus there was Anzani’s W3 back in 1907.

The 2500cc Feuling W3 engine was geared to pull a top speed of 148mph when the rev-limiter kicked in at 5500 rpm – at which point Jim claimed peak power of 154.4bhp. And after riding it – I believed him...

Gas up the throttle at a traffic light, or roll it on in top gear and your arms were yanked in their sockets while you clung frantically to the handlebars and suddenly realised why this lean but muscular-looking motorcycle had such a stretched-out riding position and rangy wheelbase; the Feuling W3 left everything else on two or four wheels eating its dust, while you fought the forces of physics and tried to stay along for the ride.

The W3 was a two-wheeled funnycar street dragster barely sanitised for the highway, which 15 years ago set new acceleration standards in commercially available powerbiking.

The W3 engine was quite a bit smoother than a 45º Harley V-twin, and idled smoothly without any trace of the shake, rattle ‘n’ roll that till then had been the American Way. This was a completely practical real-world ride – as any BMW cruiser adopting a W3 engine format would surely be too.