almost all bmw are aircooled. The K series are watercooled. but most are air. My r1100s boxer cup race bike has no watercooling. what it does have, is a massive oil cooler in the front fairing right under the headlight.
my pops r1100R has dual oil coolers on top of each opposed cylinder.
on both bikes, there is a clear glass lens so you can actually SEE the level of the oil. and when the oil level is low, the bikes run noticeably warmer according to the temp gauges.
Boxer Cup:
R1100R:
