Resizing - Briggs & Stratton 405777 Series Manual

Note: If cylinder bores are within specification and show no signs of scoring or other damage, new piston rings may be installed
providing the cylinder bores are reconditioned using a rigid hone with finishing stones, to restore the proper cross hatch angle in
the cylinder bores. The proper cylinder cross hatch ensures proper lubrication and piston ring break in.
Refer to Page 2, "Cylinder Finish" (Cross Hatch) for correct
procedure for installing cross hatch.

Resizing

Always resize to exactly .010" (25 mm) or .020" (.51 mm) or
.030" (.76 mm) over standard bore size. If this is done
accurately, the service oversize rings and pistons will fit
perfectly and proper clearances will be maintained.
Cylinders can be quickly resized with a good hone such as
Briggs & Stratton Tool #19205. Contact your Briggs &
Stratton source of supply. Use the stones and lubrication
recommended by the hone manufacturers to produce the
correct cylinder cross hatch.
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 cross hatch.
Honing is done with a variable speed 1/2", portable drill and
a honing fixture. See page 5 for dimensions to make your
own honing fixture.
Use three crankcase cover mounting screws and fasten
cylinder to a honing fixture, Fig. 3.
Clamp honing fixture and cylinder securely in a vise at a
convenient work height. Place hone drive shaft in chuck of
portable drill and tighten.
Cut a wood block and place inside cylinder to prevent hone
from extending further than 3/4" to 1" (19 mm to 25 mm)
below cylinder bore.
Place hone in middle of cylinder bore. Tighten adjusting
knob with finger until stones fit snugly against cylinder wall.
DO NOT FORCE. Connect drive shaft to hone. Be sure that
cylinder and hone are centered and aligned with drive shaft
and drill spindle.
Lubricate hone as recommended by hone manufacturer. The recommended drill speed is 300 to 700 RPM MAXIMUM and
40-60 strokes per minute. Because cylinder bores normally wear only in the area of ring travel, the cylinder bore will be round
above and below ring travel, Fig. 3. Start drill and, as hone spins, move it up and down at the bottom of the cylinder bore.
Gradually increase the length of the strokes until hone travels full length of cylinder bore, and no more than 3/4" to 1" above
cylinder bore, Fig. 3. Lubricate hone frequently to prevent build up on stones.
As cutting tension decreases, stop hone and tighten adjusting knob following hone manufacturer's recommendations. Check
cylinder bore frequently.
2
TSM
FIXTURE
WEAR
Î Î Î Î Î Î Î
RING
Î Î Î
TRAVEL
Î Î Î Î Î
UNWORN
BORE
Î Î Î Î Î
AREA
Î Î Î Î Î
Î Î
3/4" TO 1"
Ï Ï
Î Î Î Ï Ï Î Î
EXTREME
Î Î Î Ï Ï Î Î Î Î Î Î Î
HONE
TRAVEL
Î Î Î Ï Ï
AT
FINISH
Î Î Î Î Î Î Ï Ï Ï Ï Ï Ï
Ï Ï
Ï Ï Ï Ï
3/4" TO 1"
Fig. 3
MOUNTING
SCREWS
Î Î Î
Î Î Î Î Î Î
Î Î Î Î Î Î
Î Î Î Î Î Î
Î Î Î Î Î Î
Î Î Î
Î Î Î
HONE
TRAVEL
AT
START