KYMCO ZX/SCOUT 50 User Manual

6. CYLINDER HEAD/CYLINDER/PISTON
6-2
ZX / SCOUT
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
SC10AS SC10AS
Cylinder head warpage
⎯ 0.10
Piston O.D.(5mm from bottom of piston
38.95538.970 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

KYMCO ZX/SCOUT 50 Specifications

General

Brand	KYMCO
Model	ZX/SCOUT 50
Category	Scooter
Language	English