Yamaha WR450FB 2012 Owner's Service Manual page 53

Valve face width B (intake)
Valve face width B (exhaust)
Valve seat width C (intake)
Valve seat width C (exhaust)
Valve margin thickness D (intake)
Valve margin thickness D (exhaust)
Valve stem diameter (intake)
Limit
Valve stem diameter (exhaust)
Limit
Valve guide inside diameter (intake)
Limit
Valve guide inside diameter (exhaust)
Limit
Valve-stem-to-valve-guide clearance (intake)
Limit
Valve-stem-to-valve-guide clearance (exhaust)
Limit
Valve stem runout
Valve spring
Free length (intake)
Limit
Free length (exhaust)
Limit
Installed length (intake)
Installed length (exhaust)
Spring rate K1 (intake)
Spring rate K2 (intake)
Spring rate K1 (exhaust)
Spring rate K2 (exhaust)
Installed compression spring force (intake)
Installed compression spring force (exhaust)
B
C
D
2-4
ENGINE SPECIFICATIONS
2.260 mm (0.0890 in)
2.260 mm (0.0890 in)
0.90–1.10 mm (0.0354–0.0433 in)
0.90–1.10 mm (0.0354–0.0433 in)
1.00 mm (0.0394 in)
1.00 mm (0.0394 in)
4.475–4.490 mm (0.1762–0.1768 in)
4.445 mm (0.1750 in)
4.965–4.980 mm (0.1955–0.1961 in)
4.935 mm (0.1943 in)
4.500–4.512 mm (0.1772–0.1776 in)
4.550 mm (0.1791 in)
5.000–5.012 mm (0.1969–0.1973 in)
5.050 mm (0.1988 in)
0.010–0.037 mm (0.0004–0.0015 in)
0.080 mm (0.0032 in)
0.020–0.047 mm (0.0008–0.0019 in)
0.100 mm (0.0039 in)
0.010 mm (0.0004 in)
39.46 mm (1.55 in)
38.46 mm (1.51 in)
37.61 mm (1.48 in)
36.61mm (1.44 in)
27.87 mm (1.10 in)
28.38 mm (1.12 in)
12.08 N/mm (1.23 kgf/mm, 68.98 lb/in)
16.01 N/mm (1.63 kgf/mm, 91.42 lb/in)
14.34 N/mm (1.46 kgf/mm, 81.88 lb/in)
18.59 N/mm (1.90 kgf/mm, 106.15 lb/in)
130.20–149.80 N (13.28–15.28 kgf,
29.27–33.68 lbf)
123.10–141.70 N (12.55–14.45 kgf,
27.67–31.85 lbf)