6. CYLINDER HEAD/VALVE
6-7
Cylinder Head Inspection
Check if spark plug and valve holes are cracked.
Measure cylinder head warp with a straightedge
and thickness gauge.
Service limit: 0.5 mm
Valve spring free length
Measure the free length of intake and exhaust
valve springs.
Service limit: 28.90 mm
Valve stem
Check if valve stems are bend, crack or burn.
Check the operation condition of valve stem in
valve guide, and measure & record the valve stem
outer diameter.
Service Limit: IN: 4.90 mm
EX: 4.90 mm
Valve guide
Caution
Before measuring the valve guide, clean carbon
deposits with reamer.
Tool: 5.0 mm valve guide reamer
Measure and record each valve guide inner
diameters.
Service limit: 5.03 mm
The difference that the inner diameter of valve
guide deducts the outer diameter of valve stem is
the clearance between the valve stem and valve
guide.
Service Limit: IN→0.08 mm
EX→0.10 mm
5.0 mm valve guide reamer
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