Yanmar ViO12-2A, Service Manual

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4. ENGINE
4-3-7
3) Honing
(1) Application of honing
Apply honing or boring to the cylinder if it is partially
worn, flawed, or otherwise damaged. If the partial wear,
flaw or other damage is minor, it can be repaired only by
honing with a Flex-Hone. However, if it is not minor,
apply honing after boring. In this case, taking the maxi-
mum wear into consideration, it is important to examine
whether the cylinder can attain perfect roundness after
honing and / or boring, and whether prepared oversized
pistons and piston rings can be used. (For the oversized
pistons and piston rings, refer to Section "4-2-4 Piston
and Piston Rings".)
(2)
Procedure for using the Flex-Hone
It is common practice to use the Flex-Hone for honing.
The procedure for using it is described below. Any mate-
rial needs a honing allowance of approx. 1 /
1000 mm
for honing with the Flex-Hone.
[1]
Items to be prepared
Flex-Hone, power drill, and honing liquid
[2] Handling procedure
Soak the Flex-Hone in the honing liquid. Insert the Flex-
Hone into the cylinder and move it up and down for about
30 seconds while turning it at a cross hatch angle of about
30 to 40 degrees. Then, extract the Flex-Hone while turn-
ing it.
Notes :
1. Use the Flex-Hone at a speed of 300 to 1200 rpm. Use
of the Flex-Hone at a higher speed may be hazardous.
2. Never insert into or extract from the cylinder the Flex-
Hone, with the power drill stopped.
Flex-Hone
Yanmar code No.
Applicable bore dia.
mm
129400-92420 63 to 70
(Flex-Hone)
Light oil Engine oil
50% 50%
Honing liquid
Power drill
Flex-Hone
30 to 40 degrees