Aermacchi two-stroke · 1973–1978
Harley-Davidson SX, SS and SXT 125 and 175: history and buying advice
The two-strokes of the AMF era.
History
From 1973 the Varese factory built mainly two-strokes under the AMF Harley-Davidson name: first the TX 125, then the SX 125 (1974), the SXT 125 and SS 175 (1975–1978) and the SX 175. They had oil injection, so premixing was no longer needed.
In 1978 Cagiva took over the factory, and there the SXT 125 actually became a best-seller in Europe.
Key data
| Engine | Single-cylinder two-stroke, oil injection |
|---|---|
| Bore × stroke | 56 × 50 mm, c. 123 cc (SXT 125) |
| Power | c. 13 hp at the rear wheel (SXT 125) |
| Carburettor | Dell’Orto 27 mm |
| Gearbox | five speeds |
| Weight | c. 109 kg |
What to check when buying
- Oil injection: check the oil pump and lines; owners report pumps that do not work well.
- Fouled plugs and a fragile piston skirt are often mentioned: ask when it was last rebuilt.
- The electrics are weak; check the charging and the lights.
- Parts are hard to find: ask whether spares come with the bike.
- On the SX models, look for signs of off-road use on frame and suspension.