Crankcase Inspection; Crankshaft Seal Replacement - Polaris 1999 Sportsman 400 Service Manual

150
Crankcase Inspection
I. Clean both crankcase halves inside and out and
all crankcase bearin gs with cleaning so lvent. Thor-
ough ly dry with compressed air.
2. Using a scraper.
carefully rem
ove any rem ainin g
sca ler residue from all crankcase mating surfaces.
3. Carefully check the sealing surface of both
crankcase halves. Check lo r go uges or nicks that
may lead to an oil leak.
4 . C lean a ll crankcase oil passages (Figure 40)
with com pressed air.
5. Make sure the oi l pump inlet and outlet fittings
arc clear (F igure 4 1).
6. Inspect the cases for cracks and fractures, espe-
cially in the lower area s (F igu re 42) where they arc
vulnerable to rock damage. C heck the areas aro und
the stiffeni ng ribs, around bearin g bosses and
threaded holes for damage. If damage is found, have
it repa ired by a shop specializing in the repair of
precision aluminum castings or replac e the dam -
aged crankcase .
7. Chec k the threaded holes in both cra nkca se
ha lves for thread da mage, dirt or oil bui ldup. If nec-
essary, clean or repair the thread s with a suitable
size metric tap. Coat the tap threads with kerosene
or an aluminum tap fluid before use.
8. Chec k the bearings (Figu re 43 ) in each case half
for wear. Rotate the inner race of the bearing by
hand. The bearing must rotate free ly with no signs
of binding. If necessary. replace the bearing as de-
scribed in Chapter One.
9. Make sore the locating dowels are a tight-fit. Re-
fer to Figu re 44 and Figure 45. Rep lace the locat-
ing dowels if loose or severely corroded.
10. Inspect the crankshaft oil seal (F igu re 46) and
replace as descr ibed in the followi ng proced ure.
CHAPTER FIVE
C r a nkshaft Sea l Rep lacement
When rem oving the cra nksha ft seal from the right
side case half, note and record the d irect ion the seal
faces and its dep th from the c rankcase surfac e ( Fig-
ure 47) for proper installation.
Insta ll new crankcase sea ls before reassembl ing
the engine.
Refe r to Figure 48 .
I.
Pry the old seal out with a flat bladed screw-
driver or sea l removal too l ( Figure 49). Pad the pry-
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