Yamaha F25 - Page 34

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Valve spring
Free length mm (in) 39.9 (1.57)
Tilt mm (in) 1.7 (0.07)
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
Power unit technical data