By Dennis Chung
We were expecting BMW to debut its new “Big Boxer” cruisers at EICMA but were left disappointed with yet another concept model. We don’t have anything against concepts, really, but the R18/2 shown at EICMA was already the fourth to incorporate the new engine, and despite the spy photos that have popped up, it seems like BMW’s new cruisers just aren’t quite ready for full production yet.
We may be getting closer to that point now, as BMW has finally released technical details on the new R18 Big Boxer engine. We already knew the engine was an air and oil-cooled flat Twin with overhead valves manipulated by pushrods. We now know that the engine has a displacement of 1802cc from a 107mm bore and 100mm stroke, and a compression ratio of 9.6:1.
According to BMW, the engine produces 89.8 hp at 4750 rpm and more importantly for the heavyweight cruisers it’ll power, 116.5 lb-ft. at 3000 rpm, with 110 lb-ft available at just 2000 rpm. The engine speed tops out at 5750 rpm and idles at just 950 rpm. The engine itself weighs a claimed 244 pounds, and that includes the six-speed transmission and intake.
Like the BMWs of yore, the engine is air and oil cooled and uses an OHV configuration. The classic look is paired with modern technology, with four valves per cylinder, dual ignition, intake manifold injection and an engine control unit to manage all that torque while also helping the engine meet Euro 5 emission standards. Like the R 51/2 engine produced in 1950 and 1951, the engine uses two camshafts, positioning them above the crankshaft. This allows for shorter pushrods which reduces moving masses, allowing for improved control precision and stability at higher engine speeds.
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