CYLINDER HEAD/VALVES
9-3
SERVICE INFORMATION
GENERAL
• This section covers service of the cylinder head, valves, rocker arms and camshaft.
• The engine must be removed from the frame to service the rocker arms, camshaft, cylinder head and valves.
• When disassembling, mark and store the disassembled parts to ensure that they are reinstalled in their original loca-
tions.
• Clean all disassembled parts with cleaning solvent and dry them by blowing them off with compressed air before
inspection.
• The rocker arm and camshaft lubricating oil is fed through the oil passages in the cylinder head and head cover. Clean
the oil passages before assembling.
• Be careful not to damage the mating surfaces when removing the cylinder head cover and cylinder head.
SPECIFICATIONS
Unit: mm (in)
TORQUE VALUES
ITEM STANDARD SERVICE LIMIT
Cylinder compression 1,098 kPa (11.2 kgf/cm
2
, 159 psi)
at 550 rpm
–
Cylinder head warpage – 0.05 (0.002)
Rocker arm Rocker arm I.D. IN/EX 10.000 – 10.015 (0.3937 – 0.3943) 10.10 (0.398)
Rocker arm shaft O.D. IN/EX 9.972 – 9.987 (0.3926 – 0.3932) 9.91 (0.390)
Arm-to-shaft clearance IN/EX 0.013 – 0.043 (0.0005 – 0.0017) 0.08 (0.003)
Camshaft Cam lobe height IN 32.542 – 32.782(1.2812 – 1.2906) 32.52 (1.280)
EX 32.263 – 32.503 (1.2702 – 1.2796) 32.24 (1.269)
Valve, valve
guide
Valve clearance IN 0.16 ± 0.02 (0.006 ± 0.001) –
EX 0.25 ± 0.02 (0.010 ± 0.001) –
Valve stem O.D. IN 4.975– 4.990 (0.1959 – 0.1965) 4.90 (0.193)
EX 4.955 – 4.970 (0.1951 – 0.1957) 4.90 (0.193)
Valve guide I.D. IN/EX 5.000 – 5.012 (0.1969 – 0.1973) 5.03 (0.198)
Stem-to-guide
clearance
IN 0.010 – 0.037 (0.0004 – 0.0015) 0.08 (0.003)
EX 0.030 – 0.057 (0.0012 – 0.0022) 0.10 (0.004)
Valve guide projection
above cylinder head
IN/EX 9.1 – 9.3 (0.36 – 0.37) –
Valve seat width IN/EX 0.90 – 1.10 (0.035 – 0.043) 1.5 (0.06)
Valve spring
free length
IN/EX Outer 38.33 (1.509) 37.04 (1.458)
Inner 31.53 (1.241) 30.66 (1.207)
Cylinder head cover special bolt 12 N·m (1.2 kgf·m, 9 lbf·ft)
Camshaft holder nut 18 N·m (1.8 kgf·m, 13 lbf·ft) Apply engine oil to the threads and seating sur-
face.
Cam sprocket socket bolt 8 N·m (0.82 kgf·m, 5.9 lbf·ft) Apply engine oil to the threads and seating sur-
face.
Cam chain tensioner lifter screw 4 N·m (0.41 kgf·m, 3.0 lbf·ft)
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