Honda GX270T2, GX270UT2, GX390T2, GX390UT2, GX390RT2 Information Manual

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GX270T2/UT

(

)

(3)

(Use the recommended engine oil,

PISTON RING SET

SSEMBLY:

・Be sure that the top and second ring are not interchanged. ・Install the top ring and second ring on the piston with the maker

mark side facing up.

・Check that the piston rings rotate smoothly after installing them. ・Space the piston ring end gaps 120 degrees apart, and do

not align the gaps with the piston pin bore.

PISTON

PISTON PIN CLIP (20 mm) (2)

SSEMBLY:

Install by setting one end of the piston pin clip in the groove of the piston pin bore, holding the other end with long needle pliers, and rotating the clip in. Do no align the end gap of the piston pin clip with the cutout of the piston pin bore.

CUTOUT

unless otherwise specified.)

TOP RING (CHROME PLATED)

SECOND RING

OIL RING (COMBINATION RING)

END GAP

PISTON PIN CLIP

CONNECTING ROD UPPER

SSEMBLY:

Set the connecting rod upper with the long end toward the mark on the piston head.

・

MAKER MARK

PISTON PIN

GX390T2/UT2/RT

PISTON/CRANKSHAFT/BALANCER

TOP RING

Chrome plated

SECOND RING

SIDE RAIL

10 mm (0.4 in)

MARK

SPACER

SIDE RAIL

OIL RING (COMBINATION RING)

PISTON

LONG END

Engine Assembly Information

LOCK PIN (10 mm)

INSTALLATION:

・Install the lock pin immediately after installing the governor arm shaft in the direction as shown. ・The 10 mm lock pin must be installed with the straight side of the 10 mm lock pin against the groove of the governor arm shaft.

(Replace the part(s) with new one(s) before assembly.)

DRAIN PLUG WASHER (12 mm) (2) OIL LEVEL SW JOINT

NUT (10 mm)

10 N·m (1.0 kgf·m, 7 lbf·ft)

DRAIN PLUG BOLT (2)

22.5 N·m (2.25 kgf·m, 17 lbf·ft)

WASHER (8.2 x 17 x 0.8 mm)

GOVERNOR ARM SHAFT

OIL LEVEL SW (If equipped)

FLANGE BOLT (6 x 12 mm) (2)

PISTON

BALANCER WEIGHT

GROOVE

PISTON

INSTALLATION:

Install the piston to the cylinder

RIBS

barrel with the mark on the piston head toward the push rod hole of the cylinder head.

Viewed from cylinder head side

VALVE LIFTER

REMOVAL:

When removing the valve lifters, mark so that the intake and exhaust sides can be distinguished.

INSTALLATION:

ttach the valve lifters to the cylinder barrel immediately before installing the camshaft.

CAMSHAFT SIDE

CONNECTING ROD BOLT (2)

14 N·m (1.4 kgf·m, 10 lbf·ft) (Apply to

the threads and seating surface)

MARK

CRANKSHAFT

INSTALLATION:

Before installing the crankshaft, check the oil seal of the cylinder barrel for damage or hardening. Be careful not to damage the oil seal when installing the crankshaft.

BALANCER WEIGHT/CAMSHAFT INSTALLATION

Install balancer weight to the cylinder barrel by aligning the punch marks of the balancer weight and the crankshaft (marked on the balancer drive gear).

BALANCER WEIGHT

PUNCH MARKS

Install the camshaft to the cylinder barrel by aligning the punch marks of the camshaft and the crankshaft (marked on the timing gear).

CRANKSHAFT

BALANCER DRIVE GEAR

TIMING GEAR

GOVERNOR HOLDER CLIP

SSEMBLY:

Install firmly into the groove of the governor shaft.

GOVERNOR WEIGHT PIN

PLAIN WASHER

GROOVE

BALANCER/CRANKCASE COVER/GOVERNOR

GOVERNOR SLIDER

SSEMBLY:

・Spread the governor weight to install the governor slider. ・After installing the governor slider, check to be sure it moves smoothly.

GOVERNOR WEIGHT (3)

REASSEMBLY:

fter installing the governor weight, check to be sure they move smoothly.

CRANKCASE COVER

EXCEPT E TYPE

CASE COVER PACKING

DOWEL PIN (8 x 12 mm) (2)

KEY (7 x 7 x 33 mm) (6.3 x 6.3 x 43 mm) (If equipped)

CRANKCASE COVER (Without reduction type)

OIL FILLER CAP

CRANKCASE COVER (With reduction type)

PUNCH MARKS

CAMSHAFT

See the shop manual for additional information.

OIL FILLER CAP (With oil level gauge)

OIL FILLER PACKING (2)

BOLT (8 x 40 mm) (7)

24 N·m (2.4 kgf·m, 17 lbf·ft)

GX270T2/UT2

)

・

GX390T2/UT2/RT2 Engine Assembly Information

E TYPE

BOTTOM RUBBER (SMALL)

OIL FILLER CAP

OIL FILLER CAP PACKING

DUCT COVER (If equipped)

DOWEL PIN (8 x 12 mm) (2)

BOTTOM RUBBER (LARGE) (2)

CASE COVER PACKING

CASE COVER

BOLT (8 x 40 mm) (7)

24 N·m (2.4 kgf·m, 17 lbf·ft)

BOLT (5 x 10 mm) (3) (If equipped)

CRANKCASE COVER/REDUCTION UNIT/COOLING FAN/FLYWHEEL

REDUCTION TYPE

BOLT (8 x 25 mm)

DISASSEMBLY/ASSEMBLY:

Hold the 16 mm special nut of the flywheel and remove/install the 8 x 25 mm flange bolt. TORQUE: 24 N·m (2.4 kgf·m,

17 lbf·ft)

16 mm SPECIAL NUT

GEAR CASE COVER

FLANGE BOLT (8 x 40 mm) (6)

24 N·m (2.4 kgf·m, 17 lbf·ft)

PRIMARY DRIVE GEAR WASHER (8 mm)

COUNTER SHAFT

KEY (7 x 7 x 33 mm/

6.3 x 6.3 x 43 mm)

P.T.O. SHAFT

CHAIN CASE COVER PACKING

SPECIAL WOODRUFF KEY (25 x 18 mm)

DOWEL PIN (8 x 14 mm) (2)

FLYWHEEL

REMOVAL:

Hold the flywheel with a commercially available strap wrench and use the special tool to remove the flywheel. Do not hit the flywheel with a hammer.

STRAP WRENCH (Commercially available)

FLYWHEEL (Without starter)

COOLING FAN

FLYWHEEL PULLER SET 07935-8050004

FLYWHEEL

FLYWHEEL (With starter)

STARTER PULLEY (With screen)

SPECIAL NUT (16 mm)

REMOVAL:

Hold the flywheel with a commercially available strap wrench and remove the 16 mm special nut. Take care not to damage the cooling fan.

STRAP WRENCH (Commercially available)

FLYWHEEL

STARTER PULLEY (With screen)

SPECIAL NUT (16 mm)

INSTALLATION:

Clean the tapered parts of dirt, oil, grease, and other foreign material before installation. Be sure there are no metal parts or other foreign material on the magnet part of the flywheel.

"TAPERED PARTS"

lign

FLYWHEEL

pply a light coat of oil to the threads and the seating surface of the 16 mm special nut, and loosely tighten the nut. Hold the flywheel with a commercially available strap wrench, and tighten the 16 mm special nut to the specified torque. TORQUE: 170 N·m (17.3 kgf·m,

125 lbf·ft)

STRAP WRENCH

FLYWHEEL

"MAGNET PART"

STARTER PULLEY

lign

COOLING FAN

(Threads and seating surface)

COOLING FAN/FLYWHEEL/CYLINDER HEAD/VALVES

INTAKE/EXHAUST VALVE SPRING RETAINER

DISASSEMBLY:

Push down and slide the valve spring retainer to the side so that the valve stem slips through the hole at the side of the valve spring retainer. Do not remove the valve spring retainer while the cylinder head is installed to the cylinder barrel, or the valve will drop into the cylinder.

(Apply to the tappet surface and pivot)

VALVE ROCKER ARM

SSEMBLY:

Before installing the rocker arm, check for wear on the surface of the rocker arm that contact the pivot bolt, push rod, and valve stem.

PIVOT ADJUSTING NUT (2)

10 N·m (1.0 kgf·m, 7 lbf·ft)

ROCKER ARM PIVOT (2) (Apply to the threads and pivot)

8 mm PIVOT BOLT (2)

24 N·m (2.4 kgf·m, 17 lbf·ft)

PUSH ROD GUIDE PLATE

VALVE SPRING SEAT

VALVE GUIDE CLIP

EXHAUST VALVE GUIDE

CT BOLT (6 x 12 mm)

VALVE SPRING (2)

PUSH ROD (2)

SSEMBLY: Before installing the push rods, check the

ends of the push rods for wear. Be sure the ends of the push rods are firmly seated in the valve lifters.

SPARK PLUG

EXHAUST VALVE

SSEMBLY:

Do not interchange with the intake valve. VALVE HEAD DIAMETER: 31 mm

INTAKE VALVE

SSEMBLY:

Do not interchange with the exhaust valve. VALVE HEAD DIAMETER: 33 mm

INTAKE VALVE GUIDE

SHROUD

VALVE STEM SEAL

HEAD COVER PACKING

INSTALLATION:

Note the installation direction.

HEAD COVER

HEAD COVER BOLT

HEAD COVER

HEAD COVER WASHER

FLANGE BOLT (10 x 80) (4)

REMOVAL/INSTALLATION:

Loosen and tighten the four 10 x 80 mm flange bolts in a crisscross pattern in 2 - 3 steps. TORQUE: 35 N·m (3.5 kgf·m, 26 lbf·ft)

HEAD COVER PACKING

(Apply to the threads and seatin

surface

DOWEL PIN (12 x 20 mm) (2)

FAN COVER

CYLINDER HEAD GASKET

CYLINDER HEAD

INSTALLATION:

Before installing the cylinder head, remove any carbon deposits from the combustion chamber, and inspect the valve seat.

fter installing the cylinder head, measure

the cylinder compression.

See the shop manual for additional information.