Hitachi EX20UR-2 Manual page 340

(mm)
Measurement of free height and squareness
(1) Free height (free length); A
(mm)
(2) Squareness; B
Wear of valve stem
Repair the valve stem if it is stepped a little using an oil
stone.
(mm)
---------............_ Nominal Limit
Repair method
Inlet
70
6.850
Replace
Exhaust 70 6.800
Valve thickness
(mm)
Nominal
Limit Repair method
1.0 0.7 Replace
Valve spring force (tension)
Read the spring tester when compressing the spring to
the specified dimension.
(kg)
----------___,, Standard I Limit
Repair method
Compressed
to 34.7 mm
21.3 18.0 Replace
Standard Limit Repair method
45.45
44.0 Replace
Standard Limit
Repair method
2.0 or less
2.4 or more Replace
ENGINE/Engine
W05-02-24