Honda NSS250A Reflex 2001-2007, Manual

Page: 297 / 718

CYLINDER HEAD/VALVES
9-3
SERVICE INFORMATION
GENERAL
• This section covers service of the cylinder head, valves, rocker arms and camshaft.
• The cylinder head and valves can be serviced with the engine installed in the frame.
• 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.
• Camshaft and rocker arm lubricating oil is fed through oil passages in the cylinder head. Clean the oil passages before
assembling cylinder head.
• Be careful not to damage the mating surfaces when removing the cylinder head cover and cylinder head.
• For valve clearance inspection (page 4-9).
SPECIFICATIONS
Unit: mm (in)
TORQUE VALUES
ITEM STANDARD SERVICE LIMIT
Cylinder compression 1,569 kPa (16.0 kgf/cm
2
, 228 psi) at
350 min
-1
(rpm)
–
Cylinder head warpage – 0.05 (0.002)
Camshaft Cam lobe height IN 39.285 – 39.525 (1.5467 – 1.5561) 39.235 (1.5447)
EX 36.944 – 37.234 (1.4545 – 1.4659) 36.944 (1.4545)
Valve clearance IN 0.16
±
0.03 (0.006
±
0.001) –
EX 0.22
±
0.03 (0.009
±
0.001) –
Rocker arm Rocker arm I.D. IN/EX 13.000 – 13.018 (0.5118 – 0.5125) 13.10 (0.516)
Rocker arm shaft O.D. IN/EX 12.966 – 12.984 (0.5105 – 0.5112) 12.91 (0.508)
Rocker arm-to-shaft clear-
ance
IN/EX 0.016 – 0.052 (0.0006 – 0.0020) 0.08 (0.003)
Side spring free length 17.1 (0.673) 15.5 (0.61)
Valve, valve
guide Valve stem O.D. IN 4.475 – 4.490 (0.1762 – 0.1768) 4.465 (0.1758)
EX 4.465 – 4.480 (0.1758 – 0.1764) 4.455 (0.1754)
Valve guide I.D. IN/EX 4.500 – 4.512 (0.1772 – 0.1776) 4.54 (0.179)
Stem-to-guide clearance IN 0.010 – 0.037 (0.0004 – 0.0015) 0.08 (0.003)
EX 0.020 – 0.047 (0.0008 – 0.0019) 0.09 (0.004)
Valve guide projection
above cylinder head IN 11.2 – 11.5 (0.44 – 0.45) –
EX 12.2 – 12.5 (0.48 – 0.49) –
Valve seat width IN/EX 0.9 – 1.1 (0.035 – 0.043) 1.5 (0.06)
Valve spring free length IN/EX 37.09 (1.460) 35.6 (1.40)
Cam stopper plate bolt 12 N·m (1.2 kgf·m, 9 lbf·ft) Apply locking agent to the threads.
Cam sprocket bolt 16 N·m (1.6 kgf·m, 12 lbf·ft) Apply locking agent to the threads.
Cam chain tensioner lifter sealing bolt 22 N·m (2.2 kgf·m, 16 lbf·ft)
Cylinder head cover bolt 10 N·m (1.0 kgf·m, 7 lbf·ft)
Cylinder head 9 mm bolt 38 N·m (3.9 kgf·m, 28 lbf·ft) Replace with a new one.
Timing hole cap 6 N·m (0.6 kgf·m, 4.4 lbf·ft) Apply oil to the threads.
maxiscooter-club.ru