Yamaha YZ450F Owner's Service Manual page 47

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)
Spring tilt (intake)
Spring tilt (exhaust)
C
D
2-4
ENGINE SPECIFICATIONS
0.90–1.10 mm (0.0354–0.0433 in)
0.90–1.10 mm (0.0354–0.0433 in)
1.20 mm (0.0472 in)
0.85 mm (0.0335 in)
5.475–5.490 mm (0.2156–0.2161 in)
5.445 mm (0.2144 in)
5.465–5.480 mm (0.2152–0.2157 in)
5.435 mm (0.2140 in)
5.500–5.512 mm (0.2165–0.2170 in)
5.550 mm (0.2185 in)
5.500–5.512 mm (0.2165–0.2170 in)
5.550 mm (0.2185 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)
40.76 mm (1.60 in)
39.76 mm (1.57 in)
37.01 mm (1.46 in)
36.01 mm (1.42 in)
34.78 mm (1.37 in)
30.83 mm (1.21 in)
31.90 N/mm (3.25 kgf/mm, 182.15 lbf/in)
41.37 N/mm (4.22 kgf/mm, 236.22 lbf/in)
21.46 N/mm (2.19 kgf/mm, 122.54 lbf/in)
27.84 N/mm (2.84 kgf/mm, 158.97 lbf/in)
178.00–204.00 N (18.15–20.80 kgf,
40.01–45.86 lbf)
124.00–142.00 N (12.64–14.48 kgf,
27.88–31.92 lbf)
2.5 °/1.8 mm (2.5 °/0.07 in)
2.5 °/1.6 mm (2.5 °/0.06 in)