The Suzuki GS500 series originally started out in the late 70s as a 400 that didnt have electric start. Sometime during the 80s they increased the displacement to 500 to compete with the then-new Kawasaki EX500 and added electric start, which is why they added the “E” at the end, to denote electric starting. It stayed the same as a standard up until 2003 when they redesigned the tail section to look more like that of a sportbike. In 2005 they added the bodywork and changed the “E” at the end of the name to an “F” which denotes fairing. It’s still the same bike under the skin. Mechanically, it’s been the same ever since the 80s when they increased the displacement from 400cc to 500cc and added electric start. Nothing mechanically has changed since then.