Honda Metropolitan CHF50 Service Manual page 203

CRANKSHAFT/PISTON/CYLINDER
SERVICE INFORMATION
GENERAL
• This section covers the crankcase separation to service the crankshaft, piston and cylinder.
• The following parts must be removed before separating the crankcase.
- Oil pump (page 4-4)
- Water pump (page 6-9)
- Carburetor (page 5-8)
- Engine (page 7-5)
- Cylinder head/Valves (page 8-7)
- Drive pulley (page 9-9)
- Alternator/Starter (page 11-4)
• Be careful not to damage the crankcase mating surfaces when separating and assembling the crankcase halves.
• Take care not to damage the cylinder wall and piston.
• Clean all disassembled parts with clean solvent and dry them using compressed air before inspection.
SPECIFICATIONS
Unit: mm (in)
ITEM
Crankshaft
Cylinder
Piston,
piston ring,
piston pin
Connecting rod side clearance
Connecting rod radial clearance
Runout
I.D.
Out-of-round
Taper
Warpage
Piston O.D.
Piston O.D. measurement point
Piston pin bore I.D.
Piston pin O.D.
Piston-to-piston pin clearance
Piston ring-to-ring
groove clearance
Piston ring end gap
Top
Second
Top
Second
Oil (side rail)
Cylinder-to-piston clearance
Connecting rod small end I.D.
Connecting rod-to-piston pin clearance
STANDARD
0.10-0.40(0.004-0.016)
0.004 - 0.016 (0.0002 - 0.0006)
-
37.800 - 37.810 (1.4882 - 1.4886)
-
-
-
37.775 - 37.795 (1.4872 - 1.4880)
10 mm (0.39 in) from bottom of skirt
10.002 - 10.008 (0.3938 - 0.3940)
9.994 - 10.000 (0.3935 - 0.3937)
0.002 - 0.014 (0.0001 - 0.0006)
0.020 - 0.050 (0.0008 - 0.0020)
0.015 - 0.050 (0.006 - 0.0020)
0.05-0.15(0.002-0.006)
0.05-0.17(0.002-0.007)
0.10-0.60(0.004-0.024)
0.005 - 0.035 (0.0002 - 0.0014)
10.013 - 10.028 (0.3942 - 0.3948)
0.013 - 0.034 (0.0005 - 0.0013)
SERVICE LIMIT
0.60 (0.024)
0.05 (0.002)
0.10 (0.0039)
37.76 (1.487)
0.05 (0.002)
0.05 (0.002)
0.05 (0.002)
37.72 (1.485)
-
10.04(0.395)
9.98 (0.393)
0.04 (0.002)
0.08 (0.003)
0.08 (0.003)
0.40(0.016)
0.40(0.016)
0.80(0.031)
0.08 (0.003)
10.05 (0.396)
0.06 (0.002)
TORQUE VALUES
Crankcase bolt
Engine oil drain bolt
12N-m(1.2kgf-m, 9 Ibf-ft)
25 N-m (2.5 k g f m , 18 Ibf-ft)
Apply oil to the threads and seating surface
12-3