Kymco MO P50 Service Manual - chap 06 (testa cilindro pistone)
6. CYLINDER HEAD/CYLINDER/PISTON
6-0
6
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CYLINDER HEAD/CYLINDER/PISTON
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SERVICE INFORMATION........................................................ 6-2
TROUBLESHOOTING.............................................................. 6-2
CYLINDER HEAD.................................................................... 6-3
CYLINDER/PISTON................................................................. 6-6
6
6. CYLINDER HEAD/CYLINDER/PISTON
6-1
Torque: 1.5_ 1.7kg-m
Torque: 0.8_ 1.2kg-m
Torque: 1.1_ 1.7kg-m
(cold)
6. CYLINDER HEAD/CYLINDER/PISTON
6-2
SERVICE INFORMATION
GENERAL INSTRUCTIONS
• The cylinder head, cylinder and piston can be serviced with the engine installed in the frame.
• Before disassembly, clean the engine to prevent dust from entering the engine.
• Remove all gasket material from the mating surfaces.
• Do not use a driver to pry between the cylinder and cylinder head, cylinder and crankcase.
• Do not damage the cylinder inside and the piston surface.
• After disassembly, clean the removed parts before inspection. When assembling, apply the
specified engine oil to movable parts.
SPECIFICATIONS
Standard (mm)
Service Limit (mm)
Item
BA10AB.AC.50
BA10AB.AC 50
Cylinder head warpage
æ
0.10
Piston O.D.(5mm from bottom of piston
38.970_ 38.955
38.90
Cylinder-to- piston clearance
0.10
Piston pin hole I.D.
12.002_ 12.008
12.03
Piston pin O.D.
11.994_ 12.0
11.98
Piston-to-piston pin clearance
¨
¨
Piston ring end gap (top/second)
0.10_ 0.25
0.40
Connecting rod small end I.D.
17.005_ 17.017
17.03
Cylinder bore
39.0_ 39.025
39.05
TORQUE VALUES
Cylinder head bolt 1.5_ 1.7kg-m
Exhaust muffler joint lock nut 1.0_ 1.4kg-m
Exhaust muffler lock bolt 3.0_ 3.6kg-m
Spark plug 1.1_ 1.7kg-m
● TROUBLESHOOTING
Compression too low, hard starting
or poor performance at low speed Abnormal noisy piston
• Leaking cylinder head gasket • Worn cylinder and piston
• Loose spark plug • Worn piston pin or piston pin hole
• Worn, stuck or broken piston and piston rings • Worn connecting rod small end bearing
• Worn or damaged cylinder and piston
Compression too high, overheating
or knocking Abnormal noisy piston rings
• Excessive carbon build-up in cylinder head • Worn, stuck or broken piston rings
or on piston head • Worn or damaged cylinder
6. CYLINDER HEAD/CYLINDER/PISTON
6-3
CYLINDER HEAD
REMOVAL
Remove the rear carrier.
Remove the frame body cover. (!12-5)
Remove the spark plug cap.
Remove the three bolts attaching the fan
cover to remove the fan cover.
Remove the two joint lock nuts on the front
of the exhaust muffler and then remove the
two exhaust muffler lock bolts.
Remove the bolt attaching the engine hood
to remove the engine hood.
The installation sequence is the reverse of
removal.
Remove the spark plug.
Remove the cylinder head bolts and the
cylinder head.
Remove the cylinder head gasket.
Loosen the bolts diagonally in 2 or 3
times.
＊
Cylinder head Bolts
Spark Plug Cap
Fan Cover/Engine Hood
Bolts
When installing the exhaust muffler,
first tighten the two nuts on the front
and then tighten the two bolts.
＊
Cylinder Head
Spark Plug
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