Cylinder Bore Correction; Piston Pin Bushing Replacement; Oil Seal Replacement (Flywheel Housing Side) - Yanmar 2TNV70 Service Manual

4. Disassembly, Inspection and Reassembly of Engines

4.4.6 Cylinder bore correction

(a) Slight uneven worn, flawed, etc. shall be
corrected by honing only. If the cylinder is
unevenly worn partially, flawed or otherwise
damaged and cannot be repaired simply by
honing, rebore the cylinder first and then hone.
See 4.4.5.(1)(c) for the boring dimension.
(b) Items to be prepared for honing
Flex-Hone (see No.8 of 4.1.2 in Chapter 4)
Electric drill
Honing fluid (50:50 mixture of lube oil and diesel
oil)
(c) Apply the honing fluid to the Flex-Hone and turn
the electric drill at 300 to 1200 min
insert the Flex-Hone into the cylinder bore while
turning it, and move it up and down for about 30
sec. to obtain a honing mark with a cross hatch
angle of 30 to 40 .
[NOTICE]
1) Avoid faster revolution than 1200 min
may cause breakdown.
2) Do not insert or extract the Flex-Hone in stopped
state because the cylinder will be damaged.
4.4.7 Piston pin metal replacement
Replace metal by using the special service tool (see No.3 of 4.1.2 in Chapter 4).

4.4.8 Oil seal replacement (Flywheel housing side)

1) Replace an oil seal with new one when a flywheel
housing is removed. Extract the used oil seal.
2) Insert a new oil seal by using the oil seal insertion
tool on the position of the flywheel housing end
face. (Refer to the right figure.)
3) Apply lithium grease on the lip.
4) Install the flywheel housing on the cylinder block
with being careful not to damage the oil seal.
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. Then
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since it
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