Iseki SGR19 - Page 30

30
SERVICE MANUAL FOR SGR19 & SGR17
Fig. 3-31
Note:
After lapping, remove the polishing compound
completely.
(6) Inspection of valves.
• Measure the valve stem diameter with a microm-
eter.
Standard value Usable limit
Inlet valve 7.00 mm 6.90 mm
Exhaust valve 7.00 mm 6.89 mm
III II I
Valve stem end
Fig. 3-32
• Check for valve thickness.
Standard value Usable limit
Valve thickness 0.8 mm 0.55 mm
When the valve thickness is less than the usable
limit, replace the valve.
Fig. 3-33
(7) Inspection of valve springs.
• Measure the free length of each valve spring with
calipers.
Standard value Usable limit
Free length 36.0 mm 35.0 mm
Tension 8.3 kgf 7.35 kgf
(when compressed to 31 mm)
• Put a spring upright on a surface table and meas-
ure deviation from vertical.
Usable limit
Deviation from vertical 1.0 mm
Free length
Deviation from vertical
Fig. 3-34
(8) Inspection of intake and exhaust manifold con-
tact surfaces for flatness.
• Measure flatness with a straight rule and thick–
ness gauges.
Valve head thickness