BMW R 7

The BMW R 7 was a prototype of an unbuilt motorcycle from 1934, with a two-cylinder four-stroke boxer engine and shaft drive. The engineer Alfred Böning designed and built it that year, and it carried a new boxer engine by Leonhard Ischinger that was meant to come in three versions from 500 to 800 cc. The design did not go into series: BMW chose the sportier design by Rudolf Schleicher, the R 5, with a welded tubular frame instead of a lavish pressed-steel frame. The smooth-surfaced styling combined elements of Art Deco and the streamlining age. Its engine had overhead valves and was unusual in casting cylinder and head as a single piece to avoid a fragile head gasket.