SECTION
'10:
CYLINDER & CRANKCASE
COVER
It is rccommended that the cylinde.
bores be reconditioned
to restore the cross
hatch when
new
piston
rlngs
are
to be
innalled in a cylinderthat iswithin specification.
Be careful not
to
hone ove6ize or itwillbe necessarv
to
reolace
the crankcase.
Honing
is
donewithava ablespeed L2",
podab
e drilland
a honing fixture. See
Page
l0-5 for dimensions
to make a
honing fixture. Use tlvo crankcase cover mounting
scrcws to
fasten the cr€nkcaseto the honing fixturc, Figure
10-5.
Clarnp honing fixture and crankcase securely
in a
vise
at a
convenient work height.
Plac-" hone in middle of cyllnder bore. Tlghten
adjusting
knob with
finger
untilstones
fit
snugly against
cylinder
wall.
DO NOT
FORCE.
Cut a
wood
block and
place
inside
rylinder
to
prevent
hone f.om exrending further than
3/4" to 1
'
(19
mm
to
25 mm) below cylinder
bore.
Place
hone
dive shaft
in
chuck of
portable
drill and tighten. Be sure that
cylinder and
hone are centered and aligned with the drilspindle.
NOTE:
To
produ.e
the
prcper
(oss
hatch finish use a dd
speed of apyoximately
2OO RPM
and
/P-60
Hatch nrckes
per
minvte.
Lubfi.ate hone
libera
y
to
prevent
build up
on finishing stones,
NOTE: Automatic transmission fluid is
an accebtable
honing oil. Another ac.eptabte honing oit
can be tnade
by mixing 4
patts
No. 30 weight oil with
I
patt
kercsene.
with hol running wat€r
Repeatwashing
and
rinsing unlilallt€ces
oi hon n9
grh
a€
gone.
Honing
git
is
highly
abGsive and
willcause rapid wearto all
ofthe lnternal components of the engine unless
ii is
completely
Figwe
| 0-4.
Cylinder Crcss
CLEANING:
IT IS MOST IMPORTANT
THAT THE ENTIRE
CYLINDER AND
CRANKCASE
BE THOROUGHLY CLEANED
AFIER HONING.
Finwash thecylinderand crankcasecareiully in
a solventsuch
as
kercsene or commeKlal solvent. Then thorough
ywash
cy
inder
afd
cGnkcase using a stiff brush
with
soap and
hotwater
Rinsethooughy
Figurc, 0- 5. Honing Cylinde6
NofE: when cylinder and .rankcase have been thor-
oughly cleaned, use a clean white ag or napkin and
wipe the cylinder borc. ff honing
grit
is
prcsent
it wi
appear as a
gEy
rcsidue on rag. lf any honing
gfit
is evi-
dent re-wash and dnse entirc
qlinder
and
(ankcase
and
.heck again. When therc is no tace of honing
gfit
on hg.
the
qtindet
is
$ope
y
cleaned. Then oil cylindet borc
to
pfevent
fusting,
BEARINGS
CHECK MAG BEAR]NG:
Check
magneto
bearing
for damage. Damaged bearings
must be replaced. Lf not daraaged, check
for wear
using a tele-
scoping
gauge
and calper
(see
Figure 10-6). Measure
atseveral
locations. lf the measured diameter is larger than 38.25 mm
(1.506"),
the bearing must be rcplaced.
The diameter of the crankshift may also make it necessary
to rep acethe bearing.see Secrion 11 forthe cfankshaft mea-
SuTement detars.
REMOVE IV1AG BEAR NG:
2.Placecrankcaseflat upon a
pressand
remove bearing
using
a bushlng driver
(Figure
10-7).
raN
,dffiW,r.'\r'4
10-2
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