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5. Adjusting the valve clearance
CAUTION: Be sure to adjust the valve clearance with the engine sufficiently cooled down.
(1) Remove the two Screws [101] and upper Screw M4 x 25 [87] fixing the Recoil Starter [85], and then
remove the Engine Cover [102] or [104].
(2) Remove the Bolt M5 x 20 [115], and then remove the Fan Case [112].
(3) Remove the Bolt M4 x 10 [27], and then remove the Cylinder Head Cover [28]. If the Cylinder Head
Cover [28] cannot be easily removed due to liquid packing applied between the Cylinder Head Cover
[28] and Cylinder (A) [38], use a plastic hammer to lightly hit the side of the Cylinder Head Cover [28].
Be careful not to deform the Cylinder Head Cover [28] by hitting it.
(4) Remove the Spark Plug (TORCH CMR5H) [18].
(5) Slowly rotate the Magneto Rotor [122] counterclockwise. After the Exhaust Valve [41] and Intake Valve
[40] operate sequentially in this order, while looking through the Spark Plug (TORCH CMR5H) [18]
mounting hole on Cylinder (A) [38], rotate the Magneto Rotor [122] by a half turn until the Piston [51] is
positioned at the top dead center.
(6) Insert a feeler gauge between the Rocker Arm [34] and Exhaust Valve [41], and between the Rocker
Arm [34] and Intake Valve [40] to check the valve clearance. Adjust the valve clearance if it is out of
the range from 0.1 to 0.2 mm.
(7) Use a wrench to fix the lower Nut M5 [29] onto the Shaft Bolt [35]. In this status, loosen the upper Nut
M5 [29], and then loosen the lower Nut M5 [29].
NOTE: Loosening the upper Nut M5 [29] without the lower Nut M5 [29] being fixed will loosen
the Shaft Bolt [35]. Therefore, be sure to fix the lower Nut M5 [29] before loosening the
upper Nut M5 [29].
(8) Insert a 0.35-mm feeler gauge between the Rocker Arm [34] and Exhaust Valve [41] or Intake Valve
[40]. In this status, tighten the lower Nut M5 [29] until it lightly touches the Pivot Rocker Arm [30]. Then,
while fixing the lower Nut M5 [29] so that it does not turn, tighten the upper Nut M5 [29] with torque of
3.5 ± 0.5 N·m.
(9) Pull the starter knob several times, position the Piston [51] at the top dead center as described in step
(5) above, and then use a feeler gauge to check whether the valve clearance is 0.1 to 0.2 mm.
NOTE: If the lower Nut M5 [29] turns while the upper Nut M5 [29] is being tightened, the
adjusted valve clearance may exceed the range from 0.1 to 0.2 mm. Therefore, be sure
to use a wrench to fix the lower Nut M5 [29] before tightening the upper Nut M5 [29].
• Adjusting the valve clearance
Exhaust valve side
Intake valve side
