Kymco MO FILLY 50LX Service Manual - chap 07 (testa valvole)
7. CYLINDER HEAD/VALVES
7-0
FILLY LX 50
7
7
0.7-1.1kg-m
1.0-1.4kg-m
1.2-1.6kg-m
7. CYLINDER HEAD/VALVES
7-1
FILLY LX 50
SERVICE INFORMATION
GENERAL INSTRUCTIONS
• The cylinder head can be serviced with the engine installed in the frame.
• When assembling, apply molybdenum disulfide grease or engine oil to the valve guide movable
parts, valve arm and camshaft sliding surfaces for initial lubrication.
• The camshaft is lubricated by engine oil through the cylinder head engine oil passages. Clean and
unclog the oil passages before assembling the cylinder head.
• After disassembly, clean the removed parts and dry them with compressed air before inspection.
• After removal, mark and arrange the removed parts in order. When assembling, install them in the
reverse order of removal.
SPECIFICATIONS
Item
Standard (mm)
Service Limit (mm)
IN
0.04
æ
EX
0.04
æ
Cylinder head compression
14kg/cm
2
æ
Cylinder head warpage
æ
0.05
IN
26.438
26.038
EX
25.807
25.407
IN
10.000-10.015
10.10
EX
10.000-10.015
10.10
Valve rocker arm shaft
IN
9.972-9.987
9.91
O.D.
EX
9.972-9.987
9.91
IN
1.0
1.8
EX
1.0
1.8
IN
4.975-4.990
4.9
EX
4.955-4.970
4.9
IN
5.000-5.012
5.03
EX
5.000-5.012
5.03
Valve stem-to-guide
IN
0.010-0.037
0.08
clearance
EX
0.030-0.057
0.1
Inner
31.1
30.1
Outer
34.35
33.3
SERVICE INFORMATION
.....................
7-1 CYLINDER HEAD DISASSEMBLY
.......
7-7
TROUBLESHOOTING
............................
7-2 CYLINDER HEAD ASSEMBLY
..............
7-8
CAMSHAFT REMOVAL
........................
7-3 CYLINDER HEAD INSTALLATION
.....
7-8
CYLINDER HEAD REMOVAL
..............
7-5 CAMSHAFT INSTALLATION
...............
7-9
Valve clearance (cold)
Camshaft cam height
Valve rocker arm I.D.
Valve seat width
Valve stem O.D.
Valve guide I.D.
Valve spring free length
7. CYLINDER HEAD/VALVES
7-2
FILLY LX 50
TORQUE VALUES
Cylinder head nut 1.8~2.2kgf-m Apply engine oil to threads
Valve clearance adjusting nut 0.7~1.1kgf-m Apply engine oil to threads
SPECIAL TOOLS
Valve spring compressor
TROUBLESHOOTING
• The poor cylinder head operation can be diagnosed by a compression test or by tracing engine
top-end noises.
Poor performance at idle speed White smoke from exhaust muffler
• Compression too low • Worn valve stem or valve guide
• Damaged valve stem seal
Compression too low
• Incorrect valve clearance adjustment Abnormal noise
• Burned or bend valves • Incorrect valve clearance adjustment
• Incorrect valve timing • Sticking valve or broken valve spring
• Broken valve spring • Damaged or worn camshaft
• Poor valve and seat contact • Worn cam chain guide
• Leaking cylinder head gasket • Worn camshaft and rocker arm
• Warped or cracked cylinder head
• Poorly installed spark plug
Compression too high
• Excessive carbon build-up in combustion
chamber
7. CYLINDER HEAD/VALVES
7-3
FILLY LX 50
CAMSHAFT REMOVAL
Remove the center cover. (!2-3)
Remove the frame center.
Remove the four cylinder head cover bolts to
remove the cylinder head cover.
Remove the cam chain tensioner sealing bolt
and spring.
Remove the two bolts attaching the cam chain
tensioner and the tensioner.
Turn the flywheel counterclockwise so that
the “T” mark on the flywheel aligns with the
index mark on the crankcase to bring the
round hole on the camshaft gear facing up to
the top dead center on the compression
stroke.
Remove the two cylinder head bolts.
Remove the four cylinder head nuts and
washers.
Remove the camshaft holder.
Cylinder Head Cover
Sealing Bolt
Round Hole
Camshaft Gear
Bolts
Diagonally loosen the cylinder head nuts
in 2 or 3 times.
＊
Punch Marks
Washer
Nut
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