Service Manual

2-8 PERIODIC MAINTENANCE
Periodic Maintenance Procedures
Air Cleaner Housing (Case and Body) Inspection
•
Clean the housing with detergent and water and dry thor-
oughly.
•
Check the housing for deformation or other damage. The
housing must seal well and permit only filtered air to reach
the carburetor.
If the housing is damaged, it must be replaced.
•
Check that no foreign material is obstructing the air pas-
sage.
Engine Top End
Cylinder Head Cleaning and Inspection
•
Remove the cylinder head (see Engine Top End chapter).
•
Scrape the carbon deposits from the head and exhaust
port w ith a suitable tool [A ].
•
To avoid gouging, use scrapers that are made of a m ate-
rial that w ill not cause damage.
•
Clean the head in a bath of high flash-point solvent and
dry it with compressed air.
WARNING
Clean the cylinder head in a well-ventilated area,
and take care that there are no sparks or flame any-
where near the working area, this includes any ap-
pliance with a pilot light. Do not use gasoline or a
low flash-point solvent to clean the cylinder head.
A fire or explosion could result.
•
Straight edge [A] across the mating surface of the head at
several different points, and measure w arp by inserting a
thickness gauge [B] between the straightedge and head.
If warp exceeds the service limit, repair the mating sur-
face. Replace the cylinder head if the mating surface is
badly damaged.
Cylinder Head Warp
Service Limit: 0.03 mm (0.001 in.)
•
Check the cylinder head for cracks or other damage.
•
Cracks not visible to the eye may be detached by using
a m etal crack detection system (Visual color check: com-
monly found at automotive parts tore.).
•
If a crack is present in the cylinder head, replace it.
•
Inspect the mating surface for burrs and nicks.
Valve Clearance Inspection
NOTE
Valve clearance must be checked when the engine is
cold (at room temperature).
•
Remove the rocker cover (see Engine Top End chapter).
•
Place the piston at top dead center (TDC) of the compres-
sion stroke turning the crankshaft rotational direction.