There are a handful of truly iconic engines in the world of motorcycling. There ‘s the Moto Guzzi transverse, shaft-drive V. There ‘s the 45º Harley twins and the clutch-rattling 90º Ducati. Honda invented the production inline four. Yet most iconic of all may be the BMW boxer twin. Be it classic air head or modern oil head, there ‘s just something correct about those two jugs hanging low off each side of a bike.

With the 2013 R 1200 GS, BMW has done something completely new with the iconic engine: added liquid cooling. However, it ‘s important to understand that this new engine is only partially cooled by the wet stuff. As demonstrated in the video above, water cooled in the GS ‘s radiators is circulated through the engine ‘s block, cylinders and the very bottom of the drivetrain. The rest of the engine ‘s cooling is provided by good old fashioned ambient airflow.

It ‘s an interesting choice on BMW ‘s part, especially on the world ‘s most recognizable adventure bike. On one hand, liquid cooling provides a greater degree of reliability — particularly in hotter climates. On the other hand, a stone through a radiator can stall your journey in a hurry. I wonder if there ‘s a emergency service distance this new GS could travel on just air cooling alone. Regardless, the engineering is impressive and the exploded views in this video are just my kind of engine porn.

Tip of the hat goes to Hell for Leather for putting this video on our radar.