KS Motorcycles K-LIGHT125, Maintenance Manual

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XII. Cylinder head / valve
Preparatory Information ······· 12.1 Replacement of valve guide ······· 12.5
Fault Diagnosis·················· 12.2 Adjustment of valve retainer ······ 12.6
Cylinder head ··················· 12.3 Installation of cylinder head ······ 12.7
Valve inspection················· 12.4
12.1 Preparatory information
Precautions for operation
In order to ensure the sealing of cylinder head and cylinder block, the cylinder head withstands great bolt
pretightening force. Pretightening force value: 50 N·m
Before the inspection and measurement, all parts shall be cleaned and blown with high-pressure air.
Function of cylinder head: Cylinder head is used to seal the cylinder and it forms a combustion
chamber with the piston to withstand the high temperature and high pressure gas. And it can also
complete the intake and exhaust through the distribution mechanism.
Technical parameters Unit: mm
Item
Normal
Allowable
limit
Planeness of cylinder head 0.03 0.05
Valve
Valve guide
Valve clearance
Inlet 0.05-0.07
＿
Outlet 0.05-0.07
＿
Outer diameter of valve stem
Intake 5.44-5.45 5.40
Exhaust 5.435-5.445 5.40
Inner diameter of valve guide:
Intake 5.475-5.485 5.50
Exhaust 5.475-5.485 5.50
Clearance between valve stem
and valve guide
Intake 0.025-0.045 0.08
Exhaust 0.03-0.05 0.10
Width of valve seat
Intake /
exhaust
0.8-1.0 1.6
Valve spring Free length
Inner 33.5 30
Outer 40.9 39.5
Rocker arm
Outer diameter of rocker arm
shaft
Intake /
exhaust
11.98-11.988 11.95
Inner diameter of rocker arm
hole
Intake /
exhaust
12-12.018 12.05
Clearance between rocker arm
shaft and rocker arm hole
Intake /
exhaust
0.012-0.038 0.08
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