The term "airhead" applies to BMW motorcycles with Type 247 or earlier engines, which were primarily air cooled. The Type 247 engine was used from late 1969 until 1995 for some models. Beginning in 1985 or so, BMW introduced the water-cooled K-series bikes, followed by the newer air/oil cooled R-series "oilheads" in the mid-90's. Newer F and K series bike engines are also water cooled. The 2014 R Nine T keeps the oilhead style engine but stylistically pays homage to the old R90S.
1985 BMW R80RT
The 1985 R80RT, in Yukon Blue (#615). Comfortable, stately, and sporty enough. Fifty horsepower isn't a lot these days, but it will cruise the legal speed limit anywhere in the U.S. Max continuous RPM is only 7200, so it doesn't scream and whine like the UJMs.
The frame-mounted fairing provides outstanding protection from the cold and rain. One barely gets wet when riding at 40 MPH or faster.
Additional R80RT images from Google Image Search
R80RT page at the Total Motorcycle Site
Ritmo Sereno R80 Racer. Not a RT, but
still an R80.....
BMW airhead/boxer and other motorcycle links:
Airheads Beemer Club. If you have an airhead, you should belong. Provides a wealth of technical data, web site, wiki, mail lists, and the Airmail magazine. There is even airhead logos and apparel.
A&S BMW Motorcycles, good place for parts and accessories.
Barrington Motor Works, LLC, vintage BMW motorcycle restoration, parts, sales and service.
Bench Mark Works classic and antique BWM motorcycle restoration.
Bob's BMW, good place for parts and accessories.
BMW Veteran Motorcycle Club of America focused on older, (whoops, I mean more mature) BMW motorcycles. Even when they are racing at Bonneville Salt Flats.
BMWScotter's Classic BMW Motorcycles, maintenance for /5 (1970-1973) airheads.
Boxerworks Message Boards. Great source of information from Nathan's shop in Watkinsville, GA.
C.B.C. Motorcycles. Local motorcycle shop with some BMW maintenance/repair savvy.
Duane Ausherman's BMW Motorcycle repair and maintenance pages. Great hints from a former BMW motorcycle dealer and repair shop owner.
Duncan's Beemers. New England's BMW motorcycle revival and education center. An independent BMW motorcycle shop specializing in sales, repairs and parts.
Earlesfork.com Preserving vintage BMW motorcycles for the future.
Karl Kugler's Evolution Cycles.
Rubber Chicken Racing Garage, Tom Cutter's BMW and Ducati service/restoration shop.
The Saint's Airhead. That's character Simon Templar's (aka, The Saint) BMW R100RS in the series "The Return of the Saint".
Snowbum's BMW Motorcycle Repair and Information Site. Snowbum is sometimes known as Bob Fleischer.....
Speedometer Page. BMW airhead speedometers tend to be optimistic. Whether you fix it is up to you, but you should know about it.....
Apple CEO Steve Jobs used to ride a R60/2.
Ulis Motorradladen, classic BMW motorcycle parts and accessories.
The legendary and very rare R1150/2 . A newer BMW airhead 1150cc "oilhead" engine in an older /2 frame.
Over the top radial engines that can be used in motorcycles like these. Both of these configurations are probably going to show unacceptable gyroscopic reactions at high rpms. One will try to turn over on the road (just like many high-power radial engined airplanes did on take-off), the other will resist turning. Radial engines have a lot in common with narrow V-engines, including some motorcycle V-twins, that use multi-cylinder crank pins. All cylinders operate in the same plane.
Really over the top..... 48 cylinder, 4200cc motorcycle. It's not a BMW, it's not flat, but it's awesome.