Much has been said about BMW's new Concept R 18, which will soon be a regular model. First, its nostalgic styling pays homage to the great motorcycles of BMW's early days. Second, it is powered by the largest boxer-twin engine BMW has ever produced at 1800cc. Yes, you read it right: 1800cc or 1.8-liters.
Though its basic design is not too far from the ever-reliable boxer engines that BMW developed some 96 years ago, it is much more massive in size with maximum torque output of 158 Nm at only 3,000 rpm. As massive as the “Big Boxer” is, BMW kept it air and oil-cooled, but unlike the classic air-cooled 2-valve boxer engines made by BMW Motorrad, the Big Boxer crankshaft, forged from quenched and tempered steel, has an additional main bearing at the center, which was necessary due to the enormous cylinder volume in order to prevent undesirable bending vibrations of the crankshaft.
The "Big Boxer" of the BMW R 18 with Josef Miritsch, Head of BMW Motorrad Aircooled Boxer Series.
When developing the valve drive for the Big Boxer, BMW Motorrad engineers were inspired by a very special engine design from the history of BMW Motorrad – in keeping with the Heritage concept: the 2-cylinder boxer engine of the R 5/R 51 (1936 – 1941) and R 51/2 (1950 – 1951), the latter having been the first BMW motorcycle with a boxer engine after the Second World War. In contrast to other OHV designs by BMW Motorrad, this engine – highly valued by connoisseurs – has two camshafts driven by the crankshaft via a sleeve-type chain.
As has been with most BMW Motorrad boxer engines for decades (with the exception of vertical-flow, air/water-cooled boxers since 2012), a single-disc dry clutch transmits the torque generated by the engine to the 6-speed transmission. For the first time, it is designed as a self-reinforcing anti-hopping clutch, thereby eliminating unwanted stamping of the rear wheel caused by engine drag torque in the event of hard downshifting. The final drive is the classic propeller shaft which is what BMW is famous for.
Pre-orders for the 2020-2021 BMW R 18 have already started. For more info, contact RSA BMW Motorrad in Quezon City or MotorAce BMW Motorrad in Alabang. In the north of Manila, contact Laus BMW Motorrad in Pampanga.
