Installation Instructions
6. Cylinder Head / Valve 
6-9 
Valve spring free length   
Measure the free length of intake and exhaust 
valve springs. 
Service limit:   
Inner spring  35.20 mm 
Outer spring 36.90 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 
 Caution 
If clearance between valve stem and valve guide 
exceeded service limit, check whether the new 
clearance that only replaces new valve guide is 
within service limit or not.    If so, replace valve 
guide. 
Correct it with reamer after replacement. 
If clearance still exceeds service limit after 
replaced valve guide, replace valve stem too. 
 Caution 
It has to correct valve seat when replacing valve 
guide. 
5.0 mm valve guide reamer 
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