Parsun F40 EFI, Maintenance Manual

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3. Remove thermostat cover, exhaust cover, gasket and locating pin.
Check the exhaust cover for cracks, deformation or corrosion. Replace it if necessary.
4. Remove the bolts on the body in reverse order according to the serial number on the
edge of the screw hole on the engine base, and remove the engine base.
5. Remove the connecting rod bolts and connecting rod cover, remove the crankshaft, and
then remove the connecting rod and piston assembly.
6. Remove piston pin clamp spring with pliers, then remove the piston pin and piston.
7. Remove the oil seal, locating pin and bearing bush.
Piston
1. Measure the outside diameter of piston at the specified measuring point.
If it does not meet the specified value, replace it.
Diameter of piston: 64.930
～
64.945 mm
Measuring point○
a
: 3 mm
2. Check the inner diameter of piston pin hole.
If it does not meet the specified value, replace it.
Inner diameter of piston pin seat: 16.002
～
16.008 mm
Cylinder bore
1. Measure the piston outer diameter at specified measuring points○
1
○
2
○
3
.
At each measuring point, measure the diameters parallel to the crankshaft directions D1,
D3 and D5 and perpendicular to the crankshaft directions D2, D4 and D6.
Height of measuring point: ○
1
20 mm;
○
2
60 mm;
○
3
100 mm
Cylinder bore: 65.000
～
65.013 mm
2. Calculate the taper limit and roundness limit. If it exceeds the specified value, replace
the crankcase.
Taper limit: 0.08 mm (D1-D5, D2-D6)
Roundness limit: 0.05 mm (D2-D1, D6-D5)
Outside diameter of piston pin
Check the outside diameter of piston pin; If it does not meet the specified value, replace it.
Outside diameter of piston pin: 15.965
～
15.970 mm
Piston ring
1.
Check the sectional dimensions of piston ring. If it does not meet the specified value,
replace it.
Thickness Section width
Top ring
1.17
～
1.19 mm 2.39
～
2.41 mm
Second
ring
1.47
～
1.49 mm 2.49
～
2.51 mm
Oil ring
2.34
～
2.46 mm
2.75 mm
2.
Push the piston ring into the cylinder in parallel with the piston to the specified
measuring point (20mm from the joint surface).
a
D
②
③
① D1&D2
D3&D4
D5&D6