Check Cylinder; Resizing Cylinders - Briggs & Stratton Twin Cylinder L-Head Repair Manual

CHECK CYLINDER

Check cylinder for cracks, stripped threads or broken
fins. Check cylinder bores for damage or scoring.
Use telescoping gauge, Tool #19404, and dial caliper,
Tool #19199, or inside micrometer to determine the
size of the cylinder bore. Measure at six (6) points at
right angles as shown in Fig. 1. See specifications
below.
If the cylinder bore is more than .003" (.08 mm)
oversize, or .0015" (.04 mm) out of round on cast iron
sleeve cylinders, or .0025" (.06 mm) out of round on
aluminum bore cylinders, it must be resized.
STD. BORE SIZE DIAMETER
Á Á Á Á Á Á Á Á Á Á Á Á
Max.
Á Á Á Á Á Á Á Á Á Á Á Á Á Á Á Á Á Á Á Á Á Á Á Á
ALL MODELS 3.4375"
Á Á Á Á Á Á Á Á Á Á Á Á
(87.31 mm)
Á Á Á Á Á Á Á Á Á Á Á Á
NOTE: If cylinder bores are within specifi-
cation and show no signs of scoring or
other damage, new piston rings may be
installed, providing the cylinder bores are
reconditioned to restore the proper cross
hatch pattern in the cylinder bores. The
proper cylinder cross hatch ensures
proper lubrication and piston ring break in.
Refer to Page 4, "Cylinder Finish" (Cross
Hatch) for correct procedure for installing
cross hatch.

Resizing Cylinders

ALWAYS RESIZE TO EXACTLY .010" (.25 mm),
.020" (.51 mm) OR .030" (.76 mm) OVER STANDARD
SIZE AS SHOWN IN TABLE NO. 1. IF THIS IS DONE
ACCURATELY, THE STOCK OVERSIZE RINGS AND
PISTONS WILL FIT PERFECTLY AND PROPER
CLEARANCES WILL BE MAINTAINED.
Cylinders can be resized with a rigid hone such as
Briggs & Stratton Part #19205 for aluminum bore
cylinders, or Part #19211 for cast iron sleeve cylinders.
Contact your Briggs & Stratton source of supply. Use
the stones and lubrication recommended by the hone
manufacturer to produce the correct cylinder wall finish
for the various engine models.
NOTE: Automatic transmission fluid is an
acceptable honing oil. Another acceptable
honing oil can be made by mixing 4 parts
No. 30 weight oil with 1 part kerosene.
If a boring bar is used, a hone must be used after the
boring operation to produce the proper cylinder wall
cross hatch. See Cylinder Finish (Cross Hatch).
2
Á Á Á Á Á Á
Min.
Á Á Á Á Á Á Á Á Á Á Á Á
3.4365"
Á Á Á Á Á Á
(87.29 mm)
Á Á Á Á Á Á
10
MEASURE AT
CENTER OF PISTON
RING TRAVEL
Fig. 1 – Check Cylinder Bore
3/8"
FLAT
WASHERS
SCREWS
3/8"–16 UNC
2-1/2" LONG
Fig. 2
RING
WEAR
TRAVEL
UNWORN
BORE
AREA
3/4"
(19 mm)
EXTREME
HONE
TRAVEL
AT FINISH
3/4"
(19 mm)
Fig. 3
TOP
CENTER
BOTTOM
SIX POINTS
HONING
FIXTURE
SEE PAGE 8
HONE
HONE
TRAVEL
AT
START