G120F/G160F/G200F Part IV Disassembly and maintenance
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a) Check whether valve guide inner surface is smooth
and flat, whether there is any scratch or drag mark
on it; whether valve guide fits firmly with cylinder
head.
b) Ream the valve guides to remove any carbon deposits
before measuring.
Replace the guides if they are short than standard or
beyond service limit.
Replace:
a) Chill the replacement valve guide in the freezer
section of a refrigerator for about an hour.
b) Drive the valve guide out of the head from the
combustion chamber side using a valve guide driver.
When driving the valve guide out, be careful not to
damage the head.
c) Install the new valve guide from the valve spring side
of the cylinder head.
Exhaust valve: drive the valve guide until the clip is fully
seated as shown.
Intake valve: drive the intake valve guide until it
reaches the specified height (measured from top of valve
guide to cylinder head surface).
d) After installation, inspect the valve guide for damage.
Replace the guide if damaged.
Valve seat reconditioning:
For best results, be sure the cylinder head is at room
temperature before reaming the valve guide.
Standard
Service limit
5.50mm
5.572mm
Valve
guide
reamer
Valve guide driver
Correct
Wrong
