Spy shots of a BMW R1200GS prototype reveal a liquid-cooled version of the Boxer Twin. Other changes include relocated shaft drive and exhaust, and radial-mount brakes.
The photos, obtained by Motorcycle USA via spy shot specialists Brenda Priddy & Company, show a lightly camoed version of the GS. While the radiator isn’t clearly visible, the hint of a cooling fan peeks through the upper bodywork on the right side, the openings of which would vent the airflow exhaust. What looks like a cooling hose also routes up to the radiator area.
The Boxer Twin exhibits distinct changes from the 2011 version. The prominent intake tract on the current Boxer, which enters the rear of the exposed cylinder head, is notably relocated. The exhaust header pipes are also completely rerouted. While the panniers on the prototype have “R1200GS” emblazoned on the side, there’s no word on the displacement of the new engine or if the GS nomenclature will change.
Other obvious changes to the new GS come in the drive train, the final shaft drive swapped to the left side. The right side in turn gets the relocated exhaust canister – the prototype model equipped with an Akrapovic pipe.
Also updated are the GS’s front brakes, as the prototype sports stout-looking radial-mount calipers.
The move to liquid-cooling reverses almost 90 years of tradition, with BMW having produced its air-cooled Boxer Twin since 1923. The most prolific seller in BMW history (BMW produced its record-setting 100,000th R1200GS in 2007), the R1200GS has faced improved competition from rivals in the Adventure-Touring class which the GS defined. The upgrade to liquid-cooling could allow the GS to better match the engine performance of the liquid-cooled Twins powering the Ducati Multistrada and Yamaha Super Tenere.
BMW figures to debut its liquid-cooled version of the Boxer engine at this year’s wave of European bike shows
Follow the air-cooled GS’s swan song performance against its Adventure-Touring rivals all next week as we conduct the 2011 Adventure-Touring Shootout!