Sportster:   The Sportster line began in 1957 and consists of 2 major engine types over this 50 year period.   The "ironhead" Sportster was built in 900cc (57-72) and 1000cc (73-85) versions before being replaced by the "evolution or evo" engined Sportster in 1986.  Evolution sportsters are sub-divided by displacement (883, 1100, or 1200), transmission speeds 4 speed for 86-90 models and 5 speed for 91 or newer.  The evolution sportster is also sub-divided by engine mounting system.  models made through the 2003 model year use a solid engine mounting system.   2004 and newer use a rubber mount system.

Knucklehead:   Produced from 1936 until 1947 this nostalgic engine is noted for it's classic looks and overhead valve system.  Knucklehead replica engines are manufactured by several manufacturers.

PanHead:  The panhead replaced the knucklehead and was produced from 1948 until 1965.  Like the knucklehead this engine has a timeless appearance and replicas are also manufactured by several companies.

Shovelhead:  The shovel head was manufactured from 1966 until 1983.  Like the knucklehead and panhead before it this engine is also still available in replica form from several manufacturers.

Evolution (evo) - nickname - Blockhead:  The evolution engine was introduced in limited form in 1982 and became the sole bigtwin produced from 1984 on.  Like sportster evo motors the big twin evos have been manufactured in several displacements, and mount systems.  Currently made in 96 cubic inch displacements these engines are noted for their reliability and durability. 

Revolution:  The revolution engine has been produced since 2002 for the Vrod harley line.  This engine features water cooling and high performance.

Racing:  "XR" engines are considered racing engines and have been produced in a 750cc (1972-current) version that is a race-only motor and 1000cc (1983-1984) version that was used in the XR-1000 street sportster model.

Flathead:  The flathead engine was prduced in a variety of sub-types from 1929 until 1974.  This engine is most noted for its military use in WLA models and civilian/police use in 3 wheeled servicar model Harleys. 

K-model:  The K model engine was produced for the K, KH, and KHK models made from 1952 until 1956.  A race only KR version of the motor was manufactured until 1969.

Harley Main Model Lines

Sportster:  Sportster are considered to be Harleys entry models and are available in many different sub-models

Dyna/Superglide:  The Harley dyna and superglide line utilize big twin engines.  Dyna and superglide models are identified by their similar to sportster appearance utilizing a twin rear shock set-up.

Softail:  The softail line is Harleys most popular and has become the basis of 99 percent of the custom motorcycle market.  Softails are available in softail, heritage, duece (discontinued in 2008 replaced by rockster), and fatboy models.  Having a hardtail (no rear suspension) appearance these bikes can be customized as much as your bank account allows.

Touring:  Touring, sometimes refered to bagger models are available in electra-glide, road-king, and road-glide models.  Most police Harleys are based on the touring models.

Vrod:  A high performance model line these Harleys have a unique look all their own.