Cylinders; Inspect And Measure; Resizing Cylinder - Vanguard OHV V-Twin User Manual

CYLINDERS

Inspect and Measure

1. Check cylinder for cracks, stripped threads or
broken fins. Check cylinder bores for damage or
scoring.
2. Check cylinder head mounting surface for dis-
tortion with a straight edge, Fig. 1.
Replace the cylinder if the mounting surfaces are
distorted more than 0.004" (0.1 mm).
Fig. 1
3. Use Telescoping Gauge #19404 (1) and Dial
Caliper #19199 to check cylinder bores for wear.
Measure cylinder bore at 6 points as shown,
Fig. 2. Measure each cylinder bore at 90º angles
near the top (2), middle (3) and bottom (4) of
piston ring travel as shown.
If cylinder bore is worn more than 0.003"
(0.076 mm) or more than 0.0015" (0.038 mm) out-
of-round, it must be resized.
NOTE: If cylinder bores are within specification and
show no signs of scoring or damage, new
piston rings may be installed providing the
cylinder bores are reconditioned to restore
the proper crosshatch finish. Correct
cylinder bore finish
lubrication and piston ring break in.
150

Resizing Cylinder

Verify the available piston oversize(s) for the engine
being worked on. Resize the cylinder to exactly that
dimension over the standard bore size. If this is done
accurately, the oversize rings and pistons will fit
correctly, maintaining proper clearances.
Cylinders should be resized with a good quality hone
such as Briggs & Stratton Tool #19205. Contact your
Briggs & Stratton source of supply for more
information. Use the stones and lubrication
recommended by the hone manufacturer to produce
the correct cylinder finish.
NOTE: Automatic transmission fluid is an accept-
If a boring bar is used, a hone must be used after the
boring operation to produce the proper cylinder
crosshatch finish.
Honing can be done with a variable speed 1/2",
portable drill and a honing fixture. See Section 13 for
dimensions to make your own honing fixture.
1. Use crankcase cover mounting screws (2) to
2. Clamp honing fixture and cylinder securely in a
3. Cut a wood block and place inside cylinder to
4. Place hone in middle of cylinder bore. Tighten
ensures proper

Fig. 2
able honing oil. Another acceptable honing
oil can be made by mixing 4 parts 30 weight
oil with 1 part kerosene.
fasten cylinder to a honing fixture (1), Fig. 3 (A).
vise at a convenient work height. Place hone
drive shaft in chuck of portable drill and tighten.
prevent hone from extending further than 3/4 –
1" (19 – 25 mm) below cylinder bore.
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.
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