Carbon accumulation on piston and in
cylinder head (combustion chamber) is
higher than the
suspected due to damaged valve stem
or piston oil rings.
Incorrect cylinder head gasket
Damaged auto-decompressor spring or
decompressor do not move smoothly.
Exhaust gas leakage around cylinder
lower than the
Incorrect seating surface of valve.
Valve clearance is too narrow.
Piston/cylinder clearance is too wide.
Bad condition of piston ring and/or
piston ring grooves.
Auto-decompressor do not move
Cylinder Head Removal
Ignition Coil (see Ignition Coil Removal in the Electrical
Camshaft (see Camshaft Removal)
Exhaust Pipe (see Muffler Removal)
Clamp Screw [A]
Water Hose [B]
Upper Engine Bracket Bolts [A]
Upper Engine Mounting Bolts [B]
Upper Engine Brackets [C]
ENGINE TOP END 5-21
Remove the carbon deposits and replace
damaged parts if necessary.
Replace the gasket with a standard one.
Replace the spring or auto
Replace the damaged gasket and
inspect cylinder head warp.
Repair seating surface if possible.
Adjust the valve clearance.
Replace the piston and/or cylinder
Inspect the cylinder and piston; repair or
replace them if necessary.
Replace the piston and/or the piston
Replace the auto-decompressor.