HYOSUNG MS3 250 Sercie Manual page 26

2-9 PERIODIC MAINTENANCE
● Rotate the crankshaft clockwise with a socket
wrench to set the piston at TDC on the compres-
sion stroke.
(Rotate the crankshaft until the "-" line on the
magneto rotor is aligned with the triangle mark on
the magneto cover.)
● To inspect the valve clearance, insert a thickness
gauge between the tappet and the camshaft.
Valve clearance
IN.
EX.
Thickness gauge : 09900-20806
● If the clearance is out of specification, first remove
the cam chain tension adjuster, camshaft housing,
camshaft.
To install the tappet shim at original position,
record the shim NO. and clearance to present by
"A", "B", "C", "D" mark on the cylinder head.
Select the tappet that agree with tappet clearance
(vertical line) and shim NO.(horizontal line) as refer
to the tappet shim selection chart.
(Refer to page 9-37∙38)
Adjust valve timing, install the camshaft housing and
the tension adjuster.
After the crankshaft rotate about 10 times, measure
the valve clearance.
If the clearance be not correct, adjust the standard
clearance as the same manner above.
● In case of valve adjustment which is not the tappet
shim selection chart, please follow instructions of
example in the below.
For example, the intake clearance is 0.4 and the
shim is 170 (1.70 mm), select 195 (1.95 mm) of
the shim which 170 (1.70 mm) of the shim add up
the excess clearance 0.25 mm when adjust with
the standard 0.15 as the intake standard clearance
0.1� 0.2 mm.
CAUTION
If you don't rotate the crankshaft about 10 times
before measuring the valve clearance, there is no
meaning of valve clearance.
Standard (When cold)
0.10 � 0.20 mm (0.004 ~ 0.008 in)
0.20 � 0.30 mm (0.008 ~ 0.012 in)
A B
C D