Yamaha 2009 YFM25RY Service Manual page 25

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)
Spring tilt (intake)
Spring tilt (exhaust)
Winding direction (intake)
Winding direction (exhaust)
Outer 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)
Winding direction (intake)
Winding direction (exhaust)
ENGINE SPECIFICATIONS
36.17 mm (1.42 in)
34.36 mm (1.35 in)
36.17 mm (1.42 in)
34.36 mm (1.35 in)
30.50 mm (1.20 in)
30.50 mm (1.20 in)
14.70 N/mm (1.50 kgf/mm, 83.94 lbf/in)
19.00 N/mm (1.94 kgf/mm, 108.49 lbf/in)
14.70 N/mm (1.50 kgf/mm, 83.94 lbf/in)
19.00 N/mm (1.94 kgf/mm, 108.49 lbf/in)
75.00–91.70 N (7.65–9.35 kgf, 16.86–20.61
lbf)
75.00–91.70 N (7.65–9.35 kgf, 16.86–20.61
lbf)
2.5 °/1.60 mm (2.5 °/0.063 in)
2.5 °/1.60 mm (2.5 °/0.063 in)
Counterclockwise
Counterclockwise
36.63 mm (1.44 in)
34.80 mm (1.37 in)
36.63 mm (1.44 in)
34.80 mm (1.37 in)
32.00 mm (1.26 in)
32.00 mm (1.26 in)
30.90 N/mm (3.15 kgf/mm, 176.44 lbf/in)
40.80 N/mm (4.16 kgf/mm, 232.97 lbf/in)
30.90 N/mm (3.15 kgf/mm, 176.44 lbf/in)
40.80 N/mm (4.16 kgf/mm, 232.97 lbf/in)
128.50–157.90 N (13.10–16.10 kgf, 28.89–
35.50 lbf)
128.50–157.90 N (13.10–16.10 kgf, 28.89–
35.50 lbf)
2.5 °/1.60 mm (2.5 °/0.063 in)
2.5 °/1.60 mm (2.5 °/0.063 in)
Clockwise
Clockwise
2-6