SX 125

The Aermacchi-Harley-Davidson SX 125 is a light Italian two-stroke trail motorcycle from the 1970s, built in Varese and sold under the American marque. Its 123cc single, five-speed gearbox, high exhaust and simple twin shocks suit gentle road and gravel use rather than modern enduro speeds. First verify engine and frame numbers, tank graphics and model-specific parts; SX, SST and later Cagiva components are often mixed. Measure compression and listen from cold for crank-bearing noise and piston clearance. Check seals, oil pump or premix arrangement, carburettor, ignition and charging coils. A leaking tank, blocked fuel tap or hardened intake rubber causes many starting problems. Inspect the frame around steering head and footrests, fork legs, rims, spokes, drum brakes and swingarm bearings. Parts remain available through Aermacchi specialists, but original exhausts and bodywork are scarce. A complete SX 125 is light, simple and charming when restoration and tuning have been performed carefully.