Yamaha F20A Service Manual

Also see for F25A: Service manual Owner's manual Service manual Owner's manual Owner's manual

2-3SPEC EMAINTENANCE SPECIFICATIONSMAINTENANCE SPECIFICATIONSENGINEItem UnitModelWorldwide F20A F25AUSA, CANADA — F25XCYLINDER HEAD(S)Warpage limit mm (in) 0.1 (0.004)CYLINDER(S)BoreStandard mm (in) 65.000 ~ 65.015 (2.5590 ~ 2.5596)Taper limit mm (in) 0.08 (0.003)Out-of-round limit mm (in) 0.08 (0.003)CAMSHAFT(S)Intake (A) mm (in) 30.884 ~ 30.984 (1.2159 ~ 1.2198)Intake (B) mm (in) 25.95 ~ 26.05 (1.022 ~ 1.025)Exhaust (A) mm (in) 30.884 ~ 30.984 (1.2159 ~ 1.2198)Exhaust (B) mm (in) 25.95 ~ 26.05 (1.022 ~ 1.025)Camshaft journal diameter mm (in) 36.925 ~ 36.945 (1.4537 ~ 1.4545)Cylinder head journal diameter mm (in) 37.000 ~ 37.025 (1.4567 ~ 1.4577)Camshaft runout limit mm (in) 0.1 (0.0039)Cylinder block inside diameter mm (in) A: Blue 38.032 ~ 38.040 (1.4973 ~ 1.4976)B: Black 38.024 ~ 38.032 (1.4970 ~ 1.4973)C: Brown 38.016 ~ 38.024 (1.4967 ~ 1.4973)ROCKER ARM SHAFT(S)Outside diameter mm (in) 15.971 ~ 15.991 (0.6288 ~ 0.6296)ROCKER ARM(S)Inside diameter mm (in) 16.000 ~ 16.018 (0.6299 ~ 0.6306)VALVESFace angle Degree 180, 90, 60Valve clearance (cold)Intake mm (in) 0.2 ± 0.05 (0.008 ± 0.002)Exhaust mm (in) 0.3 ± 0.05 (0.012 ± 0.002)Head diameter (A)Intake mm (in) 31.9 ~ 32.1 (1.255 ~ 1.263)Exhaust mm (in) 25.9 ~ 26.1 (1.020 ~ 1.027)Face width (B)Intake mm (in) 2.3 ~ 2.7 (0.091 ~ 0.106)Exhaust mm (in) 2.5 ~ 2.9 (0.098 ~ 0.114)Seat width (C) mm (in) 0.9 ~ 1.1 (0.035 ~ 0.043)AB