GX120 ·GX160 ·GX200 Engine Assembly Information

PISTON HEAD/VALVES GX120/GX160: VALVE SPRING RETAINER EXHAUST VALVE RING MARKING DISASSEMBLY: REASSEMBLY: REASSEMBLY: TOP RING (CHROME FACED) Push down and slide the retainer to the side, so the valve ・Before installation, remove carbon deposits · Install all rings with the markings facing upward. stem slips through the hole at the side of the retainer. and inspect the valve. · Be sure that the top and second rings are not interchanged. SECOND RING (BLACK FACED) REASSEMBLY: ・Do not interchange with the valve. · Check that the rings rotate smoothly after installation. OIL RING (COMBINATION RINGS) The exhaust valve retainer has a larger center recess than VALVE HEAD DIAMETER · Space the piston ring end gaps 120 degrees apart, and the intake valve retainer so it can accept the valve rotator. GX120: IN: 22 mm (0.87 in) PISTON do not align the gaps with the piston pin . PISTON PIN CLIP NOTICE: EX: 19 mm (0.75 in) · Space the oil ring side rail end gaps at least 10 mm (0.4 in) REASSEMBLY: Do not remove the valve spring retainers while the cylinder GX160: IN: 25 mm (0.98 in) apart. Coat the oil ring with oil after assembly. Install by setting one end of the clip in PISTON PIN head is installed, or the valves will drop into the cylinder. EX: 24 mm (0.94 in) the piston groove, holding the other end with long-nosed pliers, and TOP RING VALVE ROTATOR (Exhaust valve only) CONNECTING rotating the clip in. (CHROME FACED) NOTICE: VALVE GUIDE (2) ROD Do not align the end gap of the clip SECOND RING If the valve rotator is not installed, the VALVE SPRING (2) INTAKE VALVE REASSEMBLY: Install the with the cutout in the piston pin bore. exhaust valve may drop into the cylinder PUSH ROD (2) (BLACK FACED) with the CLIP when starting the engine. REASSEMBLY: OIL RING long end toward the Check both ends for wear, (COMBINATION RINGS) triangle-marked side of PIVOT (2) and check the rod for the piston. CUT-OUT ROCKER ARM straightness. PIVOT LOCK NUT (2) Be sure the rod ends are COVER//PISTON 10 N·m (1.0 kgf·m, 7 lbf·ft) firmly seated in the lifters. ROCKER ARM PIVOT BOLT (2) 24 N·m (2.4 kgf·m, 17 lbf·ft) PISTON VALVE LIFTER REASSEMBLY: REASSEMBLY: REASSEMBLY: ROCKER ARM (2) Install with the GX200: Refer to the above for information not shown below. Install the lifters ・With the crankshaft in place, align the REASSEMBLY: triangle mark immediately before timing punch mark on the gear with Before installing, check for wear on the surfaces which contact VALVE STEM SEAL (Intake valve only) toward the installing the camshaft. the punch mark on the crankshaft gear. the pivot bolt, the push rod, and the rocker arm pivot. Replace with a new one pushrod hole. ・Before installing, inspect for worn and when reassembling. TRIANGLE MARK weakened springs and check that the INTAKE VALVE PUSH ROD HOLE decompressor weight moves smoothly. REASSEMBLY: OIL SEAL 22 x 35 x 6 mm (GX120) · Do not interchange with the exhaust valve. 25 x 41 x 6 mm Valve head diameter: Intake: 25 mm (0.98 in) Exhaust: 24 mm (0.94 in) (GX160/GX200) · Be careful not to damage the valve stem seal when installing. GOVERNOR DRIVE GEAR PUNCH MARKS PUNCH MARKS CRANKCASE CYLINDER HEAD GOVERNOR 6 x 28 (GX120) COVER 8 x 55 (4) (GX120), 8 x 60 (4) (GX160/GX200) 12 N·m (1.2 kgf·m, 9 lbf·ft) GOVERNOR WEIGHT GOVERNOR SLIDER WASHER 24 N·m (2.4 kgf·m, 17 lbf·ft) 8 x 32 (GX160/GX200) GASKET REASSEMBLY: Be sure REASSEMBLY: GREAS Do not reuse. WASHER (2) 24 N·m (2.4 kgf·m, 17 lbf·ft) REMOVAL/INSTALLATION: Do not reuse. to install the governor Install inside Loosen and tighten the weight before installing OIL SEAL the case. bolts in a crisscross pattern the crankshaft. CRANKCASE 22 x 41 x 6 mm (GX120) in 2-3 steps. 25 x 41 x 6 mm (GX160/GX200) LOCK PIN CLIP OIL DRAIN GOVERNOR REASSEMBLY: REASSEMBLY: BOLT ARM SHAFT The lock pin must be Insert firmly 18 N·m installed with the into the shaft (1.8 kgf·m, straight side of the pin groove. 13 lbf·ft) against the groove in BALL the shaft. DRAIN BOLT WASHER BEARING DOWEL PINS 6 x 12 (2) Replace. TIMING GEAR CYLINDER BARREL 10 mm NUT CONNECTING ROD BOLT CYLINDER HEAD 12 N·m (1.2 kgf·m, 9 lbf·ft) CRANKSHAFT REMOVAL/INSTALLATION: Green ( To side plate) CONNECTING ROD CAP · Before installation, remove any carbon deposits REASSEMBLY: OIL LEVEL SWITCH from the and inspect the Yellow ( To engine switch) REASSEMBLY: Push in until the bearing touches GREAS O-RING Install with the oil dipper toward the camshaft and the valve seats. the crankcase. Be careful not to REASSEMBLY: Install firmly in the groove. ribs on the cap and connecting rod are aligned. · Measure the cylinder compression after reassembly. damage the oil seal. CRANKCASE COVER

See the shop manual for additional information. © Honda Motor Co., Ltd. 2009