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78
6
E. If the top, middle and bottom bore diameters,
either parallel (A-C-E) or perpendicular (B-D-F) to
the crankshaft, vary by more than 0.003 inches
(0.08 mm), then the cylinder is excessively worn
(or tapered).
F. If cylinder is not worn beyond the service limits
described under step 10(D) and 10(E), see
DEGLAZE (RECONDITION) CYLINDER BORE.
G. If cylinder is worn beyond the service limits
described under step 10(D) and 10(E), see
HONE (RESIZE) CYLINDER BORE.
Deglaze (Recondition) Cylinder Bore
NOTE: While also restoring the proper 45° cross
hatch pattern, deglazing removes wear patterns, minor
scuff marks and scratches without enlarging the bore
diameter.
1. Tape over governor gear to keep out honing grit and
other debris.
2. To prevent damage to finishing stones, check the top
and bottom of the cylinder bore for burrs. Remove
any burrs with a fine-tooth file.
3. Obtain a three blade rigid hone with 320 grit
aluminum oxide finishing stones.
62
4. Place hone drive shaft in chuck of portable, variable
speed drill and tighten.
5. Using a suitable honing oil, liberally lubricate cylinder
bore and finishing stones.
6. Hone cylinder bore using a drill speed of
approximately 200 RPM at 40-60 strokes per minute.
7. See Figure 79. Stop frequently to examine the
cylinder bore. A precise 45° cross hatch pattern in the
piston travel area is the most important.
NOTE: The angular cross hatch pattern ensures an
even flow of oil onto the cylinder walls and promotes
longer cylinder, piston and ring life. An improper cross
hatch pattern will result in insufficient oil retention and
possible piston seizure and/or high oil consumption.
Hone (Resize) Cylinder Bore
NOTE: If lacking the necessary tools, skills, or
experience, take crankcase to a qualified machine shop
for cylinder boring.
NOTE: Resize the cylinder bore if worn 0.003 inches
(0.08 mm), or is 0.0015 inches (0.04 mm) out-of-round.
Always resize exactly 0.020 inches (0.51 mm) larger than
the standard bore diameter to ensure service oversize
piston and rings have the proper clearances.
1. Tape over governor gear to keep out honing grit and
other debris.
79
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