Polaris 1999 Sportsman 400 Service Manual page 159

ENGINE LO W ER END
tween the crank shaft whee ls. Position the tool
with its arm s con tact ing the inside of the
crank wheels evenly (in four places), then
tighten the wing nut secure ly.
c. Mount the sides of the bearing sp litter on two
wooden blocks in the press. Ce nter the cran k-
shaft under the press ram .
CAUTION
Make sure the wooden blocks are tall
enough so the
crankshaft
has mom to
press out cfits bearin g without
it
or the
connecting rodcontacting thepress bed.
WARNING
The crankshaft
will
fall once
it
is f ree
ofthe bearing. Hold the crankshaft so
it will not j;III tv the floor:
d. Press the crank shaft off its beari ng.
e. Repea t for the other bearing, if necessar y.
NOTE
T\-m methods of replacing the crank-
cas e
bearings are described in the f ol-
lowing procedure. Before starting,
153
read the Bearing Replacement section
in Chapter One fo r additional infor-
mation on bearing removal.
2A. To rep lace the bearings using heat, perform the
following steps:
a. Read thi s ste p through com pletel y and ha ve
all o f th e correc t size bearing dri vers or
soc kets on hand hefor e starting. Have all
too ls and supplies on hand to be abl e to
quickly rep lace the bearings wh ile the
cra nkcas e is hot.
NOTE
Prior to removing the right side
crankcase main bearings, the seal
must be removed.
b.
Before heating the crankcases to rep lace the
bearings, place the new bear ings in a freezer.
Chilling the m will slightly redu ce their over-
all
diameter
while
the hot crankcase is
slightly larger due to heat expans ion. This
will
make ins tallation much
easier,
c. Wash th e cases thoroughly to remove all
traces of oil a nd other chemical deposits.
d. The bearings a re installed with a slight inter-
fere nce fit. Heat the cra nkcase to a tempera-
ture of abo ut 2 12" F ( 100" C) in a shop oven
or on a ho t plat e. Heat on ly one case at a
time .
CAUTION
Do H ot heat the cases with a torch
(propane or acetylene); never bring a
fla me into contact with the
bearing or
case. The direct heat will destroy the
case hardening of the bearing and
wil/ likely ww p the case hall
e. Remo ve the ca se from the shop oven or hot
plate and hold onto the crankcase with we ld-
ing gloves- it
is hot.
NOTE
Suitable size sockets and exte nsions
can be used for removing and install-
ing bearings.
f. Support the crank case on woode n blocks and
then drive the bearing out from its opp osite
side (Figure 52). Use a bearing driver or
socket to remov e the bearing. Usc a blind
II