Harley Davidson 1986 1999 2003 Sportster Wokshop Service Repair Manual The Evolution engine (popularly known as Evo) is an air-cooled 45-degree V-Twin engine 1984 Harley-Davidson motorcycles produced for the company. It was made in the 1,340 cc (82 cu in) displacement for Harley Davidson V-twins big bikes, replacing the Shovelhead engine [...]