Service manual

ENGINE
3. Inspect cylinder for wear, scratches, or damage.
4. Inspect cylinder for taper and out of round with a
telescoping gauge or a dial bore gauge. Measure in two
different directions, front to back and side to side, on
three different levels (10mm down from top, in the middle,
and 10mm up from bottom).
5. Record measurements. If cylinder is tapered or out of
round beyond specification, the cylinder must be honed,
bored, or replaced.
Cylinder Taper
Limit: 0.05mm Max.
Cylinder Out of Round
Limit: 0.05mm Max.
CYLINDER HONE SELECTION/HONING
PROCEDURE
A hone which will straighten as well as remove material
from the cylinder is very important. Using a common
spring loaded glaze breaker for honing is not advised.
Goes recommends using a rigid hone or arbor honing
m
achine. Cylinders may be wet or dry honed depending
upon the hone manufacturer’s recommendations. Wet
honing removes more material faster and leaves a more
distinct pattern in the bore.
HONING TO DEGLAZE
A finished cylinder should have a cross-hatch pattern to
ensure piston ring seating and to aid in the retention of
the fuel/oil mixture during initial break in. Hone cylinder
according to hone manufacturer’s instructions, or these
guidelines:
◎ Use a motor speed of approximately 300-500 RPM,
run the hone in and out of the cylinder rapidly until cutting
tension decreases. Remember to keep the hone drive
shaft centered (or cylinder centered on arbor) and to
bring the stones approximately 1.3 cm above and below
the bore at the end of each stroke.
◎ Release the hone at regular intervals and inspect the
bore to determine if it has been sufficiently deglazed, and
to check for correct cross--hatch.
NOTE: Do not allow cylinder to heat up during
honing.
◎ After honing has been completed, inspect cylinder for
thinning or peeling.
IMPORTANT: Clean the Cylinder After Honing
It is very important that the cylinder be thoroughly
cleaned after honing to remove all grit material. Wash the
cylinder in a solvent, then in hot, soapy water. Use
electrical contact cleaner if necessary to clean these
areas. Rinse thoroughly, dry with compressed air, and oil
the bore immediately with 4 Cycle Lubricant to prevent
the formation of surface rust. If cylinder wear or damage
is excessive, it will be necessary to replace the cylinder.
Hone only enough to deglaze the outer layer of the
cylinder bore.
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