Rato R2000IS, Maintenance Manual

Page: 36 / 64

APPENDIX
29
Valve spring seat
：
Remove the front of valve rod from the middle of the spring seat hole.
Please noted that if the cylinder head installed on the cylinder, spring seat ring may be
dropped in the crankcase.
2
）
Inspection/Maintenance/Repairing:
①
Valve stem diameter
Using micrometer to check if the valve stem diameter is lower than the standard limit, visible
to the naked eye, more maintenance gas appearance has ablation or crack. With above
situations, you’d better to change with the new one.
Standard Maintenance Limit
3.97~3.985 mm
（
intake
）
3.935~3.95 mm
（
outtake
）
3.900 mm
（
intake
）
3.88 mm
（
outtake
）
②
Valve spring length
Measure the valve spring length.
If lower than the standard or out of
maintenance period, please use new one.
③
Valve guide pipe
Check
：
a)check whether the valve guide pipe surface smooth
or not, and without scratches and strain; valve guide
pipe should cooperate well with the cylinder head.
b) Use the valve reamer to remove the carbon deposition before measuring inner diameter.
Standard Maintenance Limit
28.5mm 27.5mm
Valve guide
reamer