Yamaha F90D - General Specifications; Maintenance Specification; Power Unit; Specifications

SPEC
Specifications
2-3
6D81G11
Maintenance specification
2
Power unit
Item Unit
Model
F90TR
Power unit
Minimum compression
pressure
(*1)
kPa
(kgf/cm
2
, psi)
860 (8.6, 124.7)
Oil pressure
(*2)
kPa
(kgf/cm
2
, psi)
510 (5.1, 74.0) at engine idle speed
Cylinder head
Warpage limit mm (in) 0.1 (0.0039)
(lines indicate straightedge
position)
Camshaft cap inside diameter mm (in) 25.000–25.021 (0.9843–0.9851)
Cylinders
Bore size mm (in) 79.000–79.020 (3.1102–3.1110)
Taper limit mm (in) 0.08 (0.0032)
Out-of-round limit mm (in) 0.05 (0.0020)
Pistons
Piston diameter (D) mm (in) 78.928–78.949 (3.1074–3.1082)
Measuring point (H) mm (in) 13.0 (0.51)
Piston clearance mm (in) 0.070–0.080 (0.0028–0.0031)
Over size piston diameter mm (in) 79.178–79.199 (3.1172–3.1181)
Piston rings
Top ring
Dimension B mm (in) 1.17–1.19 (0.0461–0.0469)
Dimension T mm (in) 2.80–3.00 (0.1102–0.1181)
End gap mm (in) 0.15–0.30 (0.0059–0.0118)
Side clearance mm (in) 0.04–0.08 (0.0016–0.0031)
2nd piston ring
Dimension B mm (in) 1.47–1.49 (0.0579–0.0587)
Dimension T mm (in) 3.00–3.20 (0.1181–0.1260)
End gap mm (in) 0.70–0.90 (0.0276–0.0354)
Side clearance mm (in) 0.03–0.07 (0.0012–0.0028)
(*1)
Measuring conditions:
Ambient temperature 20 °C (68 °F), wide open throttle, with spark plugs removed from all cylinders.
The figures are for reference only.
(*2)
The figures are for reference only.