Valve Guide
Measure clearance between the valve guide and valve stem. If the clearance exceeds the limit, replace the valve guide or valve, or both.
Standard value:
Intake 0.020 - 0.047 mm (0.0008 - 0.0019 inch)
Exhaust 0.030 - 0.054 mm (0.0012 - 0.0021 inch)
Limit:
Intake 0.10 mm (0.004 inch)
Exhaust 0.11 mm (0.004 inch)