Not sure if you remember the beautiful BMW Concept R 18 motorcycle we saw a few months ago. If you do, you may recall it was outfitted with a prototype 1,800cc flat-twin engine, but it was lacking of details to satisfy petrol heads in us. Today we have received more details on this beastly power plant.
All told, this massive two-cylinder engine featuring a vertically split aluminum engine housing puts out 91 horsepower and turns out a peak torque of 158 Nm at 3,000 rpm. It is air/oil cooled, has large ribbed cylinders and cylinder heads, and tips the scales at 110.8 kilograms including gearbox and intake system.
Other details include overhead valve drive, separate engine and transmission housing, generous flywheel mass, cast aluminum pistons, crankshaft forged from quenched and tempered steel, additional main bearing at the center of crankshaft, connecting rods with I-shaft forged from quenched and tempered steel and a wet sump lubrication system with a two-stage out pump.
The engine is paired to a constant mesh 6-speed transmission via a self-reinforcing single-plate dry clutch with anti-hopping function. The latter helps negate unwanted stamping of the rear wheel caused by engine drag torque during hard downshifting. You can learn more about BMW Motorrad Big Boxer HERE.
All images courtesy of BMW AG.