Honda NHSO aeroBO 1983, Shop Manual

Page: 51 / 184

HONDA
NHSO
6. CYLINDER H EAD/CYLINDER/PISTON
SERVICE I N FORMATION
TROUBLESHOOTING
CYLINDER HEAD
CYLINDER/PISTON
SERVICE IN FORMATION
G E N E RAL
6-1
6-1
6-2
6-4
•
All cylinder head, cylinder and piston maintenance and inspection can be done with the engine installed.
•
Before disassembly, clean the engine to prevent dirt and dust from entering the cylinder and crankcase.
•
Remove all gasket material from the mating surfaces of the cylinder head, cylinder and crankcase.
•
Use caution when disassembling and assembling the cylinder head, cylinder and piston to avoid damaging them.
•
Clean all disassembled parts thoroughly before inspection. Coat all sliding surfaces with clean motor oil before assembly.
SPECIF ICATIONS
ITEM
STAN DARD
Cylinder head Warpage
Piston Piston O.D.
47.965-47.975
mm
(1 .8884-1.8888
in)
Cylinder-to-piston clearance
0.035-0.050
mm
(0.001 3-0.0020
in)
Piston pin bore
12.002-12.008
mm
(0.4725-0.4728
in)
Piston pin O.D.
11 .994-12.000
mm
(0.4722-0.4724
in)
Piston·to·piston pin clearance
0.002-0.01 2
mm
(0.0001 -0.0005
in)
Piston ring end gap (top/second)
0.15-0.35
mm (0.006-0.014 in)
Connecting rod small end J.D.
17.005-17.017
mm (0.6695-0.6700 in)
Cylinder I . D.
48.000-48.010
mm
(1 .8898-1.8902
in)
TORQUE VALUE
Cylinder head 8-12 N ·m
(0.8-1.2
kg·m,
6-9
ft·lb)
TROUBLESHOOTING
Compression too low, hard starting or poor
performance at low speed
1.
Leaking cylinder head gasket
2.
Loose spark plug
3.
Worn, stuck or broken piston rings
4.
Worn or damaged cylinder and piston
5. Faulty reed valve
Compression too high, overheating or knocking
1.
Excessive carbon build-up in cylinder or on pis­
ton top
Date of Issue: May,
1983
© HONDA MOTOR CO., LTD.
Abnormal noise - piston
1.
Worn cylinder and piston
2.
Worn piston pin or piston pin hole
3.
Worn connecting rod small end bearing
Abnormal noise - piston rings
1. Worn, stuck or broken piston rings
2.
Worn or damaged cylinder
55
SERVICE LIMIT
0.10
mm
(0.004
in)
47.900
mm
( 1.8858
in)
0.100
mm
(0.0039
in)
1 2.025
mm
(0.4734
in)
1 1 .980
mm
(0.4717
in)
0.030
mm
(0.0012
in)
0.60
mm
(0.024
in)
17.025
mm
(0.6703
in)
48.050
mm
(1.8917
in)
6 - 1