Back in May, BMW Motorrad unveiled the Concept R18 bike at the Concorso d’Eleganza Villa d’Este as a stylish combination between old and new.
Alongside the retro appearance, the Concept R 18 also marked a return to the company’s roots thanks to a new boxer engine. Now we get to know a lot more about the new power plant which the manufacturer calls the “Big Boxer.”
It’s not hard to see why: the horizontally-opposed two-cylinder unit is the highest-capacity twin-cylinder boxer engine ever used in motorcycle series production. It has a displacement of 1,802 cc resulting from a 107.1 mm (4.2 in) bore and 100 mm (3.9 in) stroke.
As a result, it produces 91 PS (90 HP) at 4,750 rpm and a maximum torque of 158 Nm (117 lb-ft), already available at 3,000 rpm. More importantly, more than 150 Nm (111 lb-ft) of torque is on tap from 2,000 to 4,000 rpm. The maximum engine speed is 5,750 rpm while the idling speed is 950 rpm.
BMW Motorrad claims the Big Boxer engine offers “enormous pulling power” as well as “exemplary running smoothness” thanks to a generously sized flywheel mass. The new power plant is air/oil cooled, has large ribbed cylinders and cylinder heads and weighs 110.8 kg (244.2 lbs) including the gearbox and intake system.
It also has a vertically split aluminum engine housing and triple plain bearing crankcase. Interestingly, classic OHV valve drive with two camshafts is combined with modern four-valve technology and dual ignition. The transmission is a constant mesh six-speed gearbox connected to the engine via a single-plate dry clutch with anti-hopping function. A reverse gear is available as an optional extra shifted manually via an intermediate gear and an electric motor.
Wrapped in a retro-styled case, the Big Boxer engine will make its production debut in BMW Motorrad‘s upcoming R18 motorcycle.