Engine Service Manual: 162fmj

Adjust the idle speed screw until the engine runs steadily at 1,400 RPM.

Lift the cylinder head off the engine block. Remove the cylinder block (barrel) by sliding it upward off the cylinder studs. Take care not to let the piston slam against the studs.

The 162FMJ is a highly popular 150cc single-cylinder, four-stroke, air-cooled motorcycle engine. Based on the legendary Honda CG125 overhead valve (OHV) architecture, this engine powers millions of commuter motorcycles, dirt bikes, and ATVs globally. Its pushrod design makes it exceptionally durable and easy to maintain.

62.0 mm × 49.5 mm (hence the designation "62" in 162FMJ). Compression Ratio: 9.0:1 to 9.2:1 Cooling System: Natural air-cooled. 162fmj Engine Service Manual

Real-world experience has provided a valuable list of common issues:

Single-cylinder, 4-stroke, air-cooled, OHV (Pushrod). Displacement: 149.4cc Bore x Stroke: 62.0 mm × 49.5 mm

Install rings with the stamped markings (e.g., "T" or size marks) facing up . Space the ring gaps 120 degrees apart so they do not line up. Adjust the idle speed screw until the engine

The "IN" mark stamped on the piston crown must always face the Intake (carburetor) side of the engine.

Turn the square adjusting stem using valve adjustment pliers until you feel a slight, smooth drag on the feeler gauge.

If loose or tight, loosen the locknut with a 10mm wrench. Use a square-headed tappet tool or small pliers to turn the adjuster screw until there is a slight, smooth drag on the feeler gauge. Take care not to let the piston slam against the studs

Remove the three small Phillips-head screws holding the centrifugal filter outer cap.

Are you planning a or a full engine teardown ? Service manual part engine For CG-125/150

To maintain longevity, follow these intervals based on average riding conditions: Engine Oil

The manual lists the stock cam lift (usually 5.0mm). If you want more power, you can source a "race cam" (6.5mm lift), but the manual warns that exceeding the valve spring coil bind limit (found in Section 3) will destroy the engine.

9.0:1 or 9.2:1 (depends on manufacturer). Max Power: Approximately Max Torque: