Compression Pressure; Valve Clearance Specifications; Spark Plug - HYOSUNG RX 125 Service Manual

● Remove spark plug, cylinder head cover ①, and
valve timing inspection plug ②.
● Remove the magneto cover cap ③ and rotate
the magneto rotor with the 14 mm box wrench
to set the piston at (TDC) of the compression
stroke.
(Rotate the rotor until the "T"line on the rotor is
a l i g n e d w i t h t h e c e n t e r o f h o l e o n t h e
crankcase.)
● Insert the thickness gauge to the valve stem end
and the adjusting screw on the rocker arm.
Thickness gauge : 09900-20803

Valve clearance specifications

Valve clearance of IN. and EX.
● If clearance is off the specification, bring it into
the specified range by using the special tool.
Tappet adjust driver : 09917-13210
● Reinstall spark plug, cylinder head cover, valve
timing inspection plug and magneto cover cap.
CAUTION
Valve clearance should be checked when the
engine is cold.
Both the intake and exhaust valves must be
checked and adjusted when the piston is at Top-
Dead-Center (TDC) of the compression stroke.

COMPRESSION PRESSURE

NOTE:
Inspect Initial 1,000 km and Every 4,000 km.
(Refer to page 3-1)

SPARK PLUG

NOTE:
Inspect lnitial 1,000 km and 4,000 km,.
Replace Every 8,000 km.
Remove the carbon deposits with a wire or pin and
adjust the spark plug gap to 0.8~0.9 mm,
measuring with a thickness gauge.
When removing carbon deposits, be sure to
abserve the appearance of the plug, the color of
the carbon deposits. The color observed indicates
whether the standard plug is suitable or not. If the
0.08~0.13 mm
PERIODIC MAINTENANCE 2-6