Suzuki GN125F Service Manual (2014 First Edition)

Suzuki introduced the GN125 lineage in the early 1980s as a lightweight, economical small-displacement road motorcycle. Suzuki's official digital archive documents the 1982 GN125E as a 124 cm³ cruiser-style model built around a four-stroke air-cooled single-cylinder engine and five-speed transmission. That original formula of simple mechanical design, low running costs and everyday usability remained central to later GN125 derivatives sold in multiple markets.

The GN125F documented in this factory publication uses a 124 cm³ vertical air-cooled four-stroke single with a 57.0 × 48.8 mm bore and stroke and a 9.2:1 compression ratio. Fuel is supplied by a BS26 carburetor, and power passes through a wet multi-plate clutch and five-speed constant-mesh transmission. Final drive is by chain with a 43/15, or 2.867, reduction ratio and a 116-link KMC428HG chain.

Factory chassis specifications list a 1,300 mm wheelbase, 175 mm ground clearance and 113 kg curb mass. The motorcycle uses a telescopic oil-damped front fork, a swingarm rear suspension with five-position spring adjustment, a front disc brake and rear drum brake. A 10-litre fuel tank and conventional 18-inch front and 16-inch rear tire sizes reinforce its role as a simple 125cc commuter motorcycle intended for practical everyday riding and straightforward maintenance.

The service design is correspondingly conventional. The manual provides scheduled valve-clearance checks, carburetor inspection and adjustment, chain cleaning and lubrication, cable adjustment, brake-fluid service, oil and filter changes and traditional CDI-based electrical diagnosis. The engine section covers the cylinder head, camshaft, piston, crankshaft, clutch and transmission, while the final service-information section consolidates wear limits, torque values, carburetor settings and electrical specifications.

This listing is for the 148-page GN125F factory service manual, first edition dated December 2014. The source identifies the motorcycle as GN125F but does not assign a specific motorcycle model year or a continuing model-year range, so the 2014 date is treated as the manual's publication edition rather than verified vehicle-year applicability. Related publications are organized in the Suzuki GN125F manual catalog.