1. Measure:
- Valve-stem-to-valve-guide clearance. Out of specification → Replace the valve guide.
- Valve-stem-to-valve-guide clearance = Valve guide inside diameter "a" - Valve stem diameter "b"
Valve-stem-to-valve-guide clear-ance.
Valve-stem-to-valve-guide clearance (intake) 0.010-0.037 mm (0.0004-0.0015 in).
Limit 0.080 mm (0.0032 in).
Valve-stem-to-valve-guide clearance (exhaust) 0.025-0.052 mm (0.0010-0.0020 in).
Limit 0.100 mm (0.0039 in).
2. Replace:
- Valve guide
To ease valve guide removal and installation, and to maintain the correct fit, heat the cylinder head to 100°C (212°F) in an oven.
a. Remove the valve guide with the valve guide remover "1".
b. Install the new valve guide with the valve guide installer "2" and valve guide remover "1".
c. After installing the valve guide, bore the valve guide with the valve guide reamer "3" to obtain the proper valve-stem-to-valve-guide clearance.
After replacing the valve guide, reface the valve seat.
Valve guide remover (04.5) 90890-04116.
Valve guide remover (4.5 mm) YM-04116.
Valve guide remover (05) 90890-04097.
Valve guide remover (5.0 mm) YM-04097.
Valve guide installer (04.5) 90890-04117.
Valve guide installer (4.5 mm) YM-04117.
Valve guide installer (05) 90890-04098.
Valve guide installer (5.0 mm) YM-04098.
Valve guide reamer (04.5) 90890-04118.
Valve guide reamer (4.5 mm) YM-04118.
Valve guide reamer (05) 90890-04099.
Valve guide reamer (5.0 mm) YM-04099.
3. Eliminate:
- Carbon deposits (from the valve face and valve seat)
4. Check:
- Valveface
Pitting/wear → Grind the valve face.
- Valve stem end
Mushroom shape or diameter larger than the body of the valve stem → Replace the valve.
5. Measure:
- Valve margin thickness "a"
Out of specification → Replace the valve.
Valve margin thickness. Valve margin thickness D (intake) 1.35-1.75 mm (0.0532-0.0689 in). Valve margin thickness D (exhaust) 0.50-0.90 mm (0.0197-0.0354 in).
6. Measure:
- Valve stem runout
Out of specification → Replace the valve.
- When installing a new valve, always replace the valve guide.
- If the valve is removed or replaced, always replace the oil sea.
Valve stem runout 0.010 mm (0.0004 in).
