KAYO MOTOR TD125, Service Manual

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3.Check whether the cylinder head is deformed, and
check the flatness of the cylinder head with knife edge
ruler and feeler ruler;
4.Check whether the oil cap is damaged.
Check and grind valve seats
Check and grind the valve seat as follows:
The carbon deposit in the combustion chamber is
completely clean, evenly smear a thin layer of red oil on
the valve seat, put the valve on the valve seat gently tap
the valve not to rotate, and then pull out the valve, if the
contact trace on the valve working surface is
intermittent, the valve seat should be ground and
repaired.
When grinding, first remove the carbon deposit on the
inlet and exhaust valve seat, then apply the abrasive on
the valve seat, and then suck the valve with the grinding
tool of the rubber head, and grind the valve seat.
Inspection of valve guide
Measure the inner diameter of each valve guide with a
dial indicator and record it. Maintenance limit
value:φ5.035 mm
Note: Before measuring the id of the valve guide, the
carbon deposit in the valve guide should be completely
removed.
If the valve guide needs to be replaced, the valve seat
should be re-ground surface treatment, and the valve
inserted into the guide, observe its movement, and
finally calculate the clearance between the valve rod and
the valve guide.
Valve clearance maintenance limits:
Intake
：
0.07 mm
；
Exhaust
：
0.08mm.
Replacement of valve guide
1.Put the cylinder head in the thermostat to heat to 100 ~ 150 degrees Celsius, take out and support the cylinder
head (pay attention not to burn), remove with the valve. Install the tool and punch the valve guide to the side of the
rocker arm chamber.
2.Press the new valve guide into place and reaming the newly installed valve guide after the cylinder head cools.
3.The cylinder head is cleaned with cleaning agent and the metal chips in the cylinder head are removed with
compressed air.
Note: Do not damage the cylinder head when removing the valve guide.
Note: when reaming, apply cutting oil on the reamer, and rotate the reamer when loading or taking it out.
Measure width of valve seat contact area
1.Measure width of valve seat contact area. Maintenance limit value: 1.5mm
2.If the valve seat is too wide, too narrow or dented, the valve seat should be ground to achieve the correct degree
of sealing.