Yamaha F50A - Maintenance Specifications; Power Unit

SPEC
Specifications
2-5
62Y3A11
Maintenance specifications
2
Power unit
Item Unit
Model
USA ———F50TR
Canada — F50TH — F50TR
Worldwide F50AEHD F50AEHT F50AED F50AET
Power unit
Minimum compression
pressure*
kPa
(kgf/cm
2
, psi)
840 (8.4, 119)
Lubrication oil pressure
at 55 °C (131 °F), with
10W-30 engine oil
kPa
(kgf/cm
2
, psi)
@ 900 r/min
100 (1.0, 14)
Cylinder heads
Warpage limit mm (in) 0.1 (0.004)
(lines indicate straightedge
position)
Cylinder head journal inside
diameter
mm (in) 37.00–37.02 (1.4567–1.4575)
Cylinders
Bore size mm (in) 63.00–63.01 (2.480–2.481)
Taper limit mm (in) 0.08 (0.003)
Out-of-round limit mm (in) 0.05 (0.002)
Pistons
Piston diameter (D) mm (in) 62.95–62.96 (2.478–2.479)
Measuring point (H) mm (in) 5 (0.2)
Piston-to-cylinder clearance mm (in) 0.04–0.06 (0.0016–0.0024)
Oversize piston diameter
1st mm (in) + 0.25 (0.01)
2nd mm (in) + 0.50 (0.02)
Piston pins
Outside diameter mm (in) 15.965–15.970 (0.6285–0.6287)
Piston rings
Top ring
Dimension B mm (in) 1.17–1.19 (0.046–0.047)
Dimension T mm (in) 2.39–2.41 (0.094–0.095)
End gap mm (in) 0.15–0.30 (0.006–0.012)
Side clearance mm (in) 0.04–0.08 (0.0016–0.003)
* Measuring conditions:
Ambient temperature 20 °C (68 °F), wide open throttle, with plugs disconnected from all cylinders.
The figures are for reference only.