Yamaha F25 - Page 33

1-15
SPEC
Specification
Camshaft
Cam lobe height
Intake mm (in) 30.839–30.939 (1.2141–1.2181)
Exhaust mm (in) 30.937–31.037 (1.2180–1.2219)
Cam lobe width
Intake and exhaust mm (in) 25.950–26.050 (1.0217–1.0256)
Journal diameter #1 mm (in) 36.925–36.945 (1.4537–1.4545)
Journal diameter #2 mm (in) 36.935–36.955 (1.4541–1.4549)
Cylinder head journal inside
diameter
mm (in) 37.000–37.025 (1.4567–1.4577)
Runout mm (in) 0.030 (0.0012)
Rocker arm shaft
Outside diameter mm (in) 15.971–15.991 (0.6288–0.6296)
Rocker arm
Inside diameter mm (in) 16.000–16.018 (0.6299–0.6306)
Valve
Clearance
Intake mm (in) 0.20 ± 0.05 (0.008 ± 0.002)
Exhaust mm (in) 0.30 ± 0.05 (0.012 ± 0.002)
Head diameter
Intake mm (in) 31.900–32.100 (1.2559–1.2638)
Exhaust mm (in) 26.600–26.800 (1.0472–1.0551)
Seat contact width
Intake and exhaust mm (in) 1.200–1.600 (0.0472–0.0630)
Margin thickness
Intake mm (in) 0.800–1.200 (0.0315–0.0472)
Exhaust mm (in) 1.000–1.400 (0.0394–0.0551)
Item Unit
Model
F25EA
F25A T25A
Cylinder head
Warpage limit mm (in) 0.10 (0.0039)
Valve stem
Diameter
Intake mm (in) 5.475–5.490 (0.2156–0.2161)
Exhaust mm (in) 5.460–5.475 (0.2150–0.2156)
Runout
Intake and exhaust mm (in) 0.010 (0.0004)
Valve guide
Inside diameter
Intake and exhaust mm (in) 5.500–5.512 (0.2165–0.2170)
Stem-to-guide clearance
Intake mm (in) 0.010–0.037 (0.0004–0.0015)
Exhaust mm (in) 0.025–0.052 (0.0010–0.0020)
Installation position mm (in) 16.3–16.7 (0.64–0.66)
Item Unit
Model
F25MHA
F25EHA