Yamaha FZ 25 2021 - Page 40

2-3
SPEC
MAINTENANCE SPECIFICATION (ENGINE)
Camshaft
Camshaft lobe dimensions
Lobe height (Intake) 36.890–36.990 mm (1.4524–1.4563 in)
Limit 36.790 mm (1.4484 in)
Lobe height (Exhaust) 36.891–36.991 mm (1.4524–1.4563 in)
Limit 36.791 mm (1.4485 in)
Camshaft runout limit 0.030 mm (0.0012 in)
Rocker arm/rocker arm shaft
Rocker arm inside diameter 12.000–12.018 mm (0.4724–0.4731 in)
Limit 12.033 mm (0.4737 in)
Rocker arm shaft outside diameter 11.981–11.991 mm (0.4717–0.4721 in)
Limit 11.950 mm (0.4705 in)
Valve, valve seat, valve guide
Valve clearance (cold)
Intake 0.05–0.10 mm (0.0020–0.0039 in)
Exhaust 0.08–0.13 mm (0.0032–0.0051 in)
Valve dimensions
Valve seat contact width (intake) 0.90–1.20 mm (0.0354–0.0472 in)
Limit 1.7 mm (0.07 in)
Valve seat contact width (exhaust) 0.90–1.20 mm (0.0354–0.0472 in)
Limit 1.7 mm (0.07 in)
Valve stem diameter (intake) 5.975–5.990 mm (0.2352–0.2358 in)
Limit 5.950 mm (0.2343 in)
Valve stem diameter (exhaust) 5.960–5.975 mm (0.2346–0.2352 in)
Limit 5.930 mm (0.2335 in)
Valve guide inside diameter (intake) 6.000–6.012 mm (0.2362–0.2367 in)
Valve guide inside diameter (exhaust) 6.000–6.012 mm (0.2362–0.2367 in)
Valve-stem-to-valve-guide clearance (intake) 0.010–0.037 mm (0.0004–0.0015 in)
Limit 0.080 mm (0.0032 in)
Valve-stem-to-valve-guide clearance (exhaust) 0.025–0.052 mm (0.0010–0.0020 in)
Limit 0.100 mm (0.0039 in)
Valve stem runout 0.010 mm (0.0004 in)
Valve spring
Inner spring
Free length (intake) 36.17 mm (1.42 in)
Limit 34.36 mm (1.35 in)
Free length (exhaust) 36.17 mm (1.42 in)
Limit 34.36 mm (1.35 in)
Outer spring
Free length (intake) 36.63 mm (1.44 in)
Limit 34.79 mm (1.37 in)
Free length (exhaust) 36.63 mm (1.44 in)
Limit 34.79 mm (1.37 in)
B9X-F8197-E0.book Page 3 Thursday, July 16, 2020 2:28 PM