Periodic Maintenance Procedures
Cylinder Head Warp Inspection
Remove the cylinder head (see Cylinder Head Removal
in the Engine Top End chapter).
Lay a straightedge [A] across the lower surface of the
head at several different points, and measure warp by
inserting a thickness gauge [B] between the straightedge
Cylinder Head Warp
Service Limit: 0.05 mm (0.0020 in.)
If warp exceeds the service limit, repair the mating sur-
face. Replace the cylinder head if the mating surface is
Remove the valves (see Valve Removal in the Engine Top
Scrape the carbon out of the combustion chamber and
exhaust port with a scraper [A] or a suitable tool.
Clean the cylinder head, using high flash-point solvent.
Blow out any particles which may obstruct the oil passage
in the cylinder head using compressed air.
Install the valves (see Valve Installation in the Engine Top
Cylinder Wear Inspection
Measure the cylinder inside diameter when the cylinder
is cold (at room temperature).
Visually inspect the inside of the cylinder for scratches
and abnormal wear.
If the cylinder is damaged or badly worn, replace it with a
Take a side-to-side and a front-to-back measurement as
shown (total 6 measurements).
The cylinder wear is uneven in different places.
10 mm (0.39 in.) [A]
30 mm (1.2 in.) [B]
50 mm (2.0 in.) [C]
Cylinder Inside Diameter
96.025 ∼ 96.037 mm (3.7805 ∼ 3.7810
in.), and less than 0.01 mm (0.0004
in.) difference between any two
96.12 mm (3.784 in.), or more than 0.05
mm (0.002 in.) difference between any
If any of the cylinder inside diameter measurements ex-
ceeds the service limit, the cylinder must be replaced with
a new one.
Since the PLATING cylinder cannot be bored or honed.
PERIODIC MAINTENANCE 2-25