5. CYLINDER HEAD/CYLINDER/PISTON
5-2
Maintenance Information
Precautions in Operation
y
The inspection and maintenance of the cylinder head, cylinder and piston can be carried as engine
mounted on the body.
y
It should clean the engine to prevent dirt from entering into cylinder and crankcase before removal.
y
Remove all washes from the interfaces of cylinder head, cylinder and crankcase.
y
Be careful do not damage cylinder head, cylinder and piston when removing.
y
Inspect the removed & cleaned parts thoroughly, and apply with oil onto the rotation surfaces before
installation.
Specification
FT05 series
Item
Standard value (mm)
Limit (mm)
Cylinder head
Deformation
- 0.100
Piston OD
39.030~39.045
38.935
Clearance between cylinder and piston
0.040~0.050
0.100
Piston pin hole
12.002~12.008
12.030
Piston pin OD
11.994~12.000
11.970
Clearance between piston and piston pin
0.002~0.014
0.030
Piston ring end gap
0.100~0.250
0.400
Piston
ID of connecting rod small end
17.05~17.015
17.025
ID 39.000~39.015
39.050
Cylinder
Deformation -
0.100
ID: inner diameter
OD: outer diameter
Tighten torque value
Cylinder head
1.0kgf-m
Spark plug
1.4kgf-m
Exhaust pipe connection nut
1.2kgf-m
Exhaust muffler mounting bolt
3.3kgf-m
Troubleshooting
Compression Pressure Too Low/Difficult
To Start/Rough Idling
1. Cylinder head gasket leaking
2. Spark plug not tighten enough
3. Worn, seized or crack piston ring
4. Damaged, worn cylinder or piston
5. Poor reed
Compression Pressure Too
High/Overheat/Knock
1. Too much carbon deposit built up in
combustion chamber
Piston Noise
1. cylinder and piston worn out
2. piston pin or piston pin hole worn out
3. connecting rod small end bearing worn out
Piston Ring Noise
1. Worn, seized or crack piston ring
2. Cylinder worn out or damaged
This chapter Contents
Summary of Contents for DD 50
Page 1: ...DD 50 SERVICE MANUAL FORWARD HOW TO USE THIS MANUAL CONTENTS MECHANISM ILLUSTRATIONS...
Page 6: ...MODEL ILLUSTRATION FT05T FT05U FT05W Home page Contents...
Page 7: ......
Page 23: ...1 GENERAL INFORMATION 1 16 Note This chapter Contents...
Page 43: ...3 LUBRICATION SYSTEM 3 6 Notes This chapter Contents...
Page 49: ...4 ENGINE REMOVAL 4 6 Note This chapter Contents...
Page 81: ...8 FINAL DRIVING MECHANISM 8 6 Notes This chapter Contents...
Page 97: ...10 FUEL SYSTEM 10 10 Notes This chapter Contents...
Page 99: ...11 BRAKE SYSTEM 11 2 Front Drum Brake System 2 5kgf m 6 0kgf m 0 55kgf m This chapter Contents...
Page 100: ...11 BRAKE SYSTEM 11 3 Rear Drum Brake System 2 5kgf m 11 0kgf m 0 55kgf m This chapter Contents...
Page 123: ...12 BODY COVER 12 14 Note This chapter Contents...
Page 156: ...16 ELECTRICAL DIAGRAM 16 1 DD 50 ELECTRICAL DIAGRAM 16 Home page Contents...
Page 157: ...16 ELECTRICAL DIAGRAM 16 2 Notes Home page Contents...