3-7
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MAINTENANCE
COMBUSTION CHAMBER CLEANING
Remove the piston/connecting rod assembly (page 14-
4).
Prepare a cylinder of a thick paper or equivalent
material [1], which diameter is as large as to fit against
the inner wall of the cylinder, and insert the paper into
the cylinder.
Attach the special tool to an electric drill and clean any
carbon deposits from the combustion chamber.
• Be sure to insert a thick paper into the cylinder to
protect the inner wall of the cylinder during clearing
of the combustion chamber.
• Do not press the cleaning brush with force against
the combustion chamber.
VALVE CLEARANCE CHECK/
ADJUSTMENT
• Inspect and adjust the valve clearance while the
engine is cold.
CHECK
Remove the following:
– Recoil starter (page 10-2)
– Head cover (page 13-4)
Set the piston to top dead center of the compression
stroke (both valves fully closed).
Top dead center of the compression stroke is the point
where the cutout [1] in the starter pulley [2] (i.e.
opposite side from the mark [3] on the flywheel) is in
alignment with the lower bolt hole [4] of the fan cover
[5].
• If the exhaust valve opens when the cutout in the
starter pulley is aligned with the lower bolt hole on
the fan cover, turn the flywheel one turn and align
the marks.
TOOL:
Cleaning brush [2]
07998-VA20100
[1]
[2]
[2]
[4]
[5]
[3]
[1]