Briggs & Stratton 115400, Manual

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10
CYLINDER BORES
Inspect the cylinder whenever the engine has
been disassembled. Look for cracks, stripped
bolt holes, broken fins or any evidence of
cylinder wall damag e or wear.
Measuring Cylinder Bore (All Models)
Use Telescoping Gauge with a Micrometer, or
Dial Bore Gauge
#19487
to measure the cylinder
bore diameter.
Measure the cylinder bore twice at right angles at
each of the positions shown in Fig. 45.
• First two measurements, at position ( A )
at the top of the cylinder bore.
• Second two measurements, at position
( B ) in the middle of the cylinder bore.
• Third two measurements, at position ([ C ]
Fig. 45) at the bottom of the piston ring
travel in the cylinder bo re.
Fig. 45
This produces six different measurement values.
Calculate the average value of all these
measurements and compare with the
specifications listed for the engine you are
working on.
See SECTION 14- ENGINE SPECIFICATIONS.
If the cylinder bore is more than .003 in.
(.08mm) oversize or .0015 in. (.04mm) out-
of-round:
• The cylinder must be resized.
If the cylinder bore is within specification and
shows no signs of other damage:
• Recondition with finishing stones to
restore the cross-hatch.
Resizing Cylinder Bores
A cylinder bore may be resized to 0.020 in. (0.51
mm) over the standard size shown in the engine
specifications.
See SECTION 14- ENGINE
SPECIFICATIONS. If do ne accurately, the
corresponding 0.020 in. (0.51mm) oversize rings
and pistons will fit correctly and maintain proper
clearances.
Cylinders can be resized with a good quality
hone set.
For aluminum bore engines:
• Briggs & Stratton Hone Set
(#19205)
For sleeve bore engines:
• Briggs & Stratton Hone Set
(#19211)
Consult the Briggs & Stratton Service Tools
Catalog
(MS-8746)
for specific hone set contents.
If a boring bar is used to resize a cylinder
bore:
• A finish hone must be used to produce
the proper cross-hatch texture.
CAUTION:
Honing grit is impossible to remove
from a ball bearing. Remove ball bearing from cyl-
inder before honing or rapid w ear of the be aring
will result.
1. Fasten cylinder to a honing fixture or a
heavy iron bracket. Use a level to align
drill press spindle with cylinder bo re.
Some cylinders require shims.
2. Check cylinder bores at top and bottom for
burrs. Remove burrs to prevent damage
to hon e.
NOTE:
(085400, 115400, 117400, 138400,
161400, 185400, 235400, 245400) These
models have cylinders bores that are 30°
degrees from the horizontal plane. The honing
fixture must hold the base of the cylinder at 60°
degrees from ho rizontal for the cylinder bore to
be vertical.
3. When available, fasten cylinder ( A ) to a
honing fixture ( B ), with clamp ( C ) and
shims ([ D ] Fig. 46).