Yamaha E40J - Maintenance Specification; Power Unit

SPEC
2-3
6F65G11
Specifications
Maintenance specification
Power unit
Item Unit
Model
E40GMH E40GWH E40JMH E40JWH E40JW
Power unit
Minimum compression kPa 480 (4.8, 70)
pressure (*1) (kgf/cm
2
, psi)
Cylinder head
Warpage limit mm (in) 0.1 (0.0039)
(lines indicate straightedge
position)
Cylinders
Bore size mm (in) 78.000–78.020 (3.0709–3.0716)
Wear limit mm (in) 78.100 (3.0700)
Taper limit mm (in) 0.08 (0.0032)
Out-of-round limit mm (in) 0.05 (0.0020)
Pistons
Piston diameter (D) mm (in) 77.940–77.965 (3.0685–3.0695)
Measuring point (H) mm (in) 10.0 (0.39)
Piston-to-cylinder clearance mm (in) 0.055–0.060 (0.0022–0.0024)
(limit) 0.110 (0.0043)
Piston pin boss bore mm (in) 19.904–19.915 (0.7836–0.7841)
Oversize piston
1st mm (in) 0.25 (0.010)
2nd mm (in) 0.50 (0.020)
Oversize piston diameter
1st mm (in) 78.190–78.215 (3.0783–3.0793)
2nd mm (in) 78.440–78.465 (3.0882–3.0892)
Piston pins
Outside diameter mm (in) 19.895–19.900 (0.7833–0.7835)
(*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.