Yamaha XG250 Service Manual page 20

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
Cylinder head valve seat width (intake)
Limit
Cylinder head valve seat width (exhaust)
Limit
Valve spring
Inner 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)
C
D
ENGINE SPECIFICATIONS
0.90–1.10 mm (0.0354–0.0433 in)
0.90–1.10 mm (0.0354–0.0433 in)
0.80–1.20 mm (0.0315–0.0472 in)
0.80–1.20 mm (0.0315–0.0472 in)
5.975–5.990 mm (0.2352–0.2358 in)
5.950 mm (0.2343 in)
5.960–5.975 mm (0.2346–0.2352 in)
5.935 mm (0.2337 in)
6.000–6.012 mm (0.2362–0.2367 in)
6.042 mm (0.2379 in)
6.000–6.012 mm (0.2362–0.2367 in)
6.042 mm (0.2379 in)
0.010–0.037 mm (0.0004–0.0015 in)
0.080 mm (0.0032 in)
0.025–0.052 mm (0.0010–0.0020 in)
0.100 mm (0.0039 in)
0.030 mm (0.0012 in)
0.90–1.10 mm (0.0354–0.0433 in)
1.7 mm (0.07 in)
0.90–1.10 mm (0.0354–0.0433 in)
1.7 mm (0.07 in)
36.17 mm (1.42 in)
34.47 mm (1.36 in)
36.17 mm (1.42 in)
34.47 mm (1.36 in)
30.50 mm (1.20 in)
30.50 mm (1.20 in)
14.70 N/mm (83.94 lb/in) (1.50 kgf/mm)
19.00 N/mm (108.49 lb/in) (1.94 kgf/mm)
14.70 N/mm (83.94 lb/in) (1.50 kgf/mm)
19.00 N/mm (108.49 lb/in) (1.94 kgf/mm)
75.00–91.70 N (16.86–20.61 lb) (7.65–9.35 kgf)
75.00–91.70 N (16.86–20.61 lb) (7.65–9.35 kgf)
2-4