Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionCylinder Head Cover Installation
Replace the cylinder head cover gasket [A] with a new
one
Using a high flash-point solvent, clean off any oil or dirt
that may be on the silicone sealant coating area. Dry
them with a clean cloth.
Apply silicone sealant [B] to the cylinder head as shown
in the figure.
Sealant - Li ...
Rear Master Cylinder Installation
Replace the washers that are on each side of hose fitting
with new ones.
Install the brake hose [A].
Touch the brake hose to the stopper [B] of the rear master
cylinder.
Tighten:
Torque - Brake Hose Banjo Bolt: 25 N·m (2.5 kgf·m, 18 ft·lb)
Install the master cylinder, the brack ...
Cylinder Head Warp Inspection
Clean the cylinder head.
Lay a straightedge across the lower surface of the cylinder
head at several positions.
Use a thickness gauge [A] to measure the space between
the straightedge [B] and the head.
Cylinder Head Warp
Standard: – – –
Service Limit: 0.05 mm (0.0020 in.)
...