Quote Originally Posted by MCMXCIVRS View Post
The water cooling appears to be used just for the heads, specifically the area around the valves, hence the remaining cooling fins on the cylinders.
Good observation. A few month's ago, Kevin Cameron's column in Cycle World focused on H-D's interest in water-cooling its Big Twin's, specifically at the exhaust valve area, to reduce excessive heat. Oil "coking" was noted as a problem. He also mentioned that BMW had included oil drainage relief in their oilheads so that the effects of coking near the valves were minimized.

I imagine that BMW couldn't increase displacement & HP any further under the opposed-twin design with oil cooling. Hence, the Wethead.

Without getting into the other pro's & con's of the new design, I trust that those more-exposed headers are resistant to corrosion. My old Suzuki GSX-1100F's headers were sandblasted by debris throw up from the front tire. I ended up having them treated by Jet Hot to remove the corrosion.