Hyosung GV650 Pro / GT650 FI Service Manual Supplement (2012)

Hyosung began its modern middleweight expansion with the GT650 Comet, introduced internationally in 2004. Earlier Comet roadsters had been smaller motorcycles, but the 650 established a new technical platform around a liquid-cooled 647 cc, eight-valve, double-overhead-cam 90-degree V-twin. Its steel-framed naked-roadster layout, six-speed transmission and twin front discs made it an alternative to established middleweight street motorcycles. A contemporary 2004 industry report documents the launch, the original carbureted engine and Hyosung's ambition to reach a broader international market.

The Comet lineage expanded with GT650, GT650P, GT650S and GT650R variants, broadening the shared engine platform into naked, alternative roadster, semi-faired and fully faired configurations. The S and R models appeared during the mid-2000s, while the later P designation was used for an updated naked-roadster configuration. Despite their different cockpit, bodywork and ergonomic packages, the Comet family retained a six-speed gearbox and chain final drive. Design changes across successive versions included revised tail sections, cockpit instruments, brakes and sporting bodywork. The Hyosung owners' model chronology records the early S/R introductions and the 2009 GT revisions.

Hyosung also adapted its 647 cc V-twin architecture to the GV650 Aquila, a longer and lower power cruiser introduced during the middle of the decade. Its broad rear tyre, stretched wheelbase, lower seating position and forward-set controls placed it in a different segment from the Comet sport and street machines. Mechanically, the cruiser used a five-speed gearbox and belt final drive, in contrast to the Comet's six-speed chain system. In 2012 the GV650 Pro developed that cruiser branch with a redesigned rear end, revised two-into-one exhaust and updated trim while retaining the underlying engine concept. The Pro variant reached additional markets in 2013, as documented in a period launch report.

Electronic injection became an important step in the evolution of both families after their original carbureted years. The first EFI variants arrived in the late 2000s, introducing ECU-controlled fuel delivery and electronic sensor diagnostics. By the 2012 revision, D-spec models used an updated injection and electrical architecture, with revised fault-code and instrument-display behavior. The same period saw changes to the GT650R's bodywork and suspension. These developments created a later-generation fuel-injected V-twin platform whose service requirements differed materially from the earlier carbureted and first-generation EFI motorcycles, although the familiar 81.5 mm by 62.0 mm engine bore and stroke remained unchanged.

The Aquila Pro and D-spec Comet machines represent an evolutionary stage in Hyosung's 650 range rather than a completely new engine family. The motorcycles retained distinct cruiser and road-sport identities while adopting further fuel-system, electrical and chassis changes. The manufacturer's October 2012 publication includes a specific 2013-model GT650R front-fork section, illustrating the transition into the following model year. Related earlier editions are available in the Hyosung manual catalog. This edition concentrates on D-spec electronic-injection differences and selected 2013 chassis work; its model-family history should not be confused with a guarantee that every production-year variation is covered by the same technical procedures.