162fmj — Engine Service Manual

The 162FMJ engine is a staple in the world of 150cc motorcycles, pit bikes, and light utility vehicles. Often manufactured by brands like Zongshen, Lifan, and Shineray, this air-cooled, four-stroke, single-cylinder engine is prized for its simple overhead valve (OHV) design and remarkable durability.

3. Key Service Data for 162FMJ (compiled from clone specs)

| Parameter | Value | |-----------|-------| | Displacement | ~124–125 cc | | Bore × Stroke | 62 × 49.5 mm (common) or 62 × 52.9 mm | | Compression ratio | 9.0:1 to 9.5:1 | | Valve clearance (cold) | 0.05 mm (IN) / 0.08 mm (EX) | | Spark plug | A7TC (NGK C7HSA) — 0.6–0.7 mm gap | | Oil capacity | 0.9–1.0 L (10W-40 or 15W-40) | | Idle speed | 1400–1500 RPM | | Primary kick start + electric start | Yes | | Transmission | 4-speed (N-1-2-3-4) semi-auto or manual | 162fmj Engine Service Manual

Engine won't start: Spark -> Fuel -> Compression (in that order)
Low compression: Check valves, head gasket, piston rings.
Engine knocks: Connecting rod big end bearing wear or incorrect octane fuel.

The crate arrived wrapped in oil-stained burlap, tied with wire that had rusted into place years ago. There was no return address, only a faded label: “162fmj Engine Service Manual – For the Eyes of the Last Mechanic.” The 162FMJ engine is a staple in the

16: Bore size (62mm).
2: Cylinder count (Single cylinder).
F: Air-cooled (though some variants are oil-cooled).
M: Motorcycle engine configuration.
J: Specific manufacturer designations (often refers to the displacement class—typically 196cc to 202cc).