Operational Precautions; Trouble Diagnosis - Sym Orbit 125 Service Manual

11. CRANKCASE/CRANKSHAFT

OPERATIONAL PRECAUTIONS

General Information
This Section contains descriptions concerning disassembly of the crankcase so that the
crankshaft can be serviced.
Complete following operations before disassembling crankcase.
Engine
Cylinder head
Cylinder and piston
V-belt Drive pulley
AC generator/ Starting Clutch
If the crankshaft bearing or timing sprocket need be replaced, then the crankshaft set have to
replaced.
Specification
Left, right clearance of the big end of the connecting rod
Radial clearance of the big end of the connecting rod
Run-out
Torque value
Bolts for crankcase
Bolts for cylinder/cylinder head
Engine oil draining plug
Bolts for cam chain tensioner
Special Service Tools
Crankcase remover/set
Crankshaft installation puller
Inner type bearing puller
Outer type bearing puller
Bearing pressing tools
Oil seal pressing tools

TROUBLE DIAGNOSIS

Engine noise
• Loose crankshaft bearing
• Loose crankshaft pin bearing
• Wear piston pin or piston pin hole
11-2
Item
Chapter 5
Chapter 6
Chapter 7
Chapter 8
Chapter 10
Standard
0.100~0.350
0.000~0.008
─
0.8~1.2 kgf-m
0.7~1.0 kgf-m
3.5~4.5 kgf-m
0.8~1.2 kgf-m
SYM
Unit: mm
Limit
0.550
0.050
Below 0.030