Kymco XCITING 500 - Service Manual > Cylinder Head Removal

Remove the rock arms.

Remove the two bolts, intake pipe and insulator.

Remove the two bolts, two nuts, pair reed valve and gasket.

Remove the two bolts, water joint, gasket and water stop collar.

Remove the three bolts and cylinder head.

Remove the dowel pins and cylinder head gasket.

DISASSEMBLY

CYLINDER HEAD DISASSEMBLY

Remove the valve spring cotters, retainers, springs, spring seats, oil seals and valves using a valve spring compressor.

• Be sure to compress the valve springs with a valve spring compressor.
• Mark all disassembled parts to ensure correct reassembly.

Special tool: Valve Spring Compressor E040

• Valve Spring Cotters
• Retainers
• Valves
• Springs
• Spring Seats
• Oil Seals

VALVE /VALVE GUIDE INSPECTION

Inspect each valve for bending, burning, scratches or abnormal stem wear.

If any defects are found, replace the valve with a new one.

Check valve movement in the guide.

Measure each valve stem O.D.

Measure each valve guide I.D.

Subtract each valve stem O.D. from the corresponding guide I.D. to obtain the stem-to-guide clearance.

Service limits:
  IN: 0.08 mm (0.0032 in)
  EX: 0.1 mm (0.004 in)

If the stem-to-guide clearance exceeds the service limits, replace the cylinder head is necessary.

CYLINDER HEAD INSPECTION

Check the spark plug hole and valve areas for cracks.

Check the cylinder head for warpage with a straight edge and feeler gauge.

Service Limit: 0.05 mm (0.002 in)

VALVE SPRING INSPECTION

Measure the free length of the inner and outer valve springs.

Service Limit:
  Inner: 35.2 mm (1.408 in)
  Outer: 39.8 mm (1.592 in)

Measure compressed force (valve spring) and installed length.

Replace if out of specification.

Standard:
  Inner: 3.5 kg (at 28.7 mm, 1.148 in)
  Outer: 13 kg (at 31.43 mm, 1.2572 in)

Measure the spring tilt.

Replace if out of specification.

Standard:
  Inner: 1.2 mm (0.048)
  Outer: 1.2 mm (0.048)

ASSEMBLY

Install the valve spring seats and oil seal.

Be sure to install new oil seal.

Lubricate each valve with engine oil and insert the valves into the valve guides.

Install the valve springs with the small-pitch portion (1) facing cylinder head. (2) Large-pitch portion.

Put on the valve sparing retainers.

Compress the valve springs using the valve spring compressor, then install the valve cotters.

• When assembling, a valve spring compressor must be used.
• Install the cotters with the pointed ends facing down from the upper side of the cylinder head.

Special tool: Valve Spring Compressor E040

Tap the valve stems gently with a plastic hammer for 2～3 times to firmly seat the cotters.

Be careful not to damage the valves.

See also: