EM/Engine Mechanical, page 28

EM-28                    ENGINE MECHANICAL — Cylinder Head

(d) Hand lap the valve and valve seat together with abrasive compound.
(e) Clean the valve and valve seat after hand-lapping.

13. INSPECT VALVE SPRINGS
(a) Using a steel square, check the squareness of the valve springs.
Maximum: 2.0 mm (0.079 in.)
If squareness is greater than maximum, replace the valve spring.

(b) Measure the free height of all springs.
Free height:
Intake side    49.1 mm (1.933 in.)
Exhaust side  52.5 mm (2.067 in.)
Replace any spring that is not correct.

(c) Using a spring tester, check the tension of each spring at the specified installed height.
Installed height:
Intake side    40.0 mm (1.575 in.)
Exhaust side  43.0 mm (1.693 in.)
Installed tension:
Intake side    34.7 — 38.3 kg
               (76.5 — 84.4 lb, 340 — 376 N)
Exhaust side  33.3 — 36.7 kg
               (73.4 — 80.9 lb, 327 — 360 N)
If not within the installed tension specification, replace the spring.

14. INSPECT INTAKE, EXHAUST MANIFOLDS AND AIR IN-TAKE CHAMBER
Using a precision straight edge and feeler gauge, check the surfaces contacting the cylinder head for warpage.
Maximum intake warpage:   0.1 mm (0.004 in.)
Maximum exhaust warpage: 0.75 mm (0.0295 in.)
Maximum air intake chamber warpage:  0.1 mm
                                      (0.004 in.)
If warpage is greater than maximum, replace the manifold or air intake chamber.