1.802cc, 91hp and 158Nm, 110.8kg
Air / oil cooling, OHV distribution with two shafts and 4 valves, 6-speed anti-roll …
Leader of the trail segment with its R 1250 GS, BMW Motorrad is present today in all market segments, from scooter to hypersportive, but the Bavarian manufacturer is still absent from the cruisers. An absence that will soon be filled by the arrival of the R 18.
We know that the brand will expand its Heritage range of a new heavy-duty machine since the official presentation of the R 18 concept at the Concorso d'Eleganza Villa d'Este last May. Since then, the propeller brand has introduced a second concept and opened pre-orders, but the series model is still waiting.
BMW unveils a little more about its future R 18 by presenting in detail its brand new flatbed twin engine Big Boxer. If the engine plays the vintage card from outside, it also retains some "historic" features, such as its OHV (OverHead Valve) distribution, its separate crankcase and transmission.
Above all, we find ourselves facing the biggest Boxer ever produced since the cubic capacity reaches 1.802 cm3 with bore values of 107.1 mm and stroke of 100 mm. The Big Boxer will be able to develop 91 horses at 4,750 rpm and a torque of 158 Nm at 3,000 rpm. The latter will also reach 150 Nm between 2,000 and 4,000 rpm. The idle is set at 950 rpm and the maximum speed at 5.750 rpm.
With a weight of 110.8 kg with its transmission and intake, the twin is equipped with an air / oil cooling system, a vertically divided aluminum engine block and a triple sliding bearing assembly.
If it focuses on modernity with its four valves, dual ignition, direct injection, engine management BMS-O, its reduced emissions or its modern combustion chamber, the Big Boxer opts for a very classic configuration with a distribution by overhead valves. Engineers here were inspired by the boxers of the R5 / R51 and R51 / 2, maintaining the double camshaft system to reduce moving masses, minimize deformation and limit linear expansion.
Actuation of the two inlet and outlet valves in the head of each cylinder is provided by a fork rocker arm. In addition, the compensation of the valve clearance is here not hydraulic, but provided by a set screw with locknut.
At the level of the clutch, there is a single-disc dry and self-reinforced element which is associated with a six-speed cabot box housed in a two-section aluminum casing. Finally, the final transmission is ensured by a cardan shaft.
It will now wait a little longer before discovering the final design of the BMW R 18 series, the characteristics of its cycle, its price and availability.
More info about BMW Motorrad