Hyosung Karion RT125 Service Manual (2002)

Hyosung entered motorcycle production in 1978 and expanded from its early technical relationship with Suzuki into independently developed motorcycles during the following decade. By the early 2000s the company was broadening its 125 cc range with models aimed at younger riders and practical everyday transport. The Karion arrived in that period as an unusual alternative to conventional lightweight enduros: its styling and proportions mixed dual-purpose cues with exceptionally wide tires and a low, compact stance. Hyosung's corporate history provides the broader background to the company's move into independently developed motorcycles.

The Karion was already represented by a dedicated factory workshop manual in November 2002, while European catalog sources place its commercial introduction around 2002-2003. The early motorcycle used a 124.5 cm³ air-cooled SOHC single with a 57 × 48.8 mm bore and stroke, a PD18F piston-valve carburetor and five-speed constant-mesh transmission. Electric starting was backed by a kick starter. The chassis specification was deliberately distinctive: 130/80-18 front and 180/80-14 rear tires, 230 mm ground clearance, telescopic fork, swingarm rear suspension and simple front-disc/rear-drum braking. Those proportions gave the bike a visual identity closer to a compact “fat-tire” trail machine than a traditional narrow-tire 125 enduro.

The RT125 designation identifies that first Karion platform in Hyosung's model coding. Its 2,085 mm overall length, 1,350 mm wheelbase and 135 kg mass made it more substantial than a stripped-down competition 125, while the 9-litre fuel tank and relaxed SOHC engine supported everyday use. The combination of large-section tires, moderate suspension travel and low-speed tractability defined the model as a wide-tire 125 cc dual-purpose motorcycle aimed as much at urban and recreational riding as at unpaved roads.

The original RT125 generation did not remain the only Karion configuration. Application catalogs separate the early RT125 Karion from the later RT125D, and Hyosung/S&T's later supplementary engine manual explicitly describes the RT125D as a different engine specification while telling technicians to refer back to the original Karion manual for unchanged systems. That later generation moved to a DOHC four-valve engine, creating a clear technical break from the SOHC platform documented here. Contemporary parts and spark-plug application data likewise distinguish the pre-2007 SOHC RT125 from the later RT125D generation.

This listing is therefore tied to the original factory publication rather than the previous broad 2002-2008 catalog range. The source is Hyosung Motors & Machinery Inc. Service Manual No. 99000-94610, explicitly marked “1st Ed. NOV. 2002,” and its cover identifies the Karion. Because the manual itself does not state that it applies unchanged through 2008, catalog coverage is conservatively limited to 2002. Related factory publications are grouped in the Hyosung Karion manual catalog.