With only a few moving parts -- two-strokes lack complex ... can lead to valve or piston failures. In 1968, the VW air-cooled 4-cylinder engine became the first to offer electronic fuel injection ...

Introduced in 1957 as a counterpart to the West German VW ... of parts to assemble have helped the engine remain reliable. Thanks to its relatively simple design, Harley-Davidson's air-cooled ...

Air-cooled engines are simpler, which means cheaper, and actually translates into more reliability. There aren't as many parts that can fail, and without the threat of overheating, they can pretty ...