Upper Crankcase Preparation; Piston Ring Installation - Polaris ACE 900 2017 Service Manual

ENGINE / COOLING SYSTEM
Bearing Selection Chart - Main Bearings
Code B
Blue
1
Case
2 Blue
3 Green

UPPER CRANKCASE PREPARATION

NOTICE
Always replace plain bearings when the crankcase or
connecting rods have been disassembled. Refer to
bearing selection procedures.
1. Remove all traces of crankcase sealer from the
crankcase mating surfaces. Inspect the surfaces
closely for nicks, burrs or damage.
2. Clean bolt hole threads to remove any oil or
crankcase sealant.
3. Inspect crankcase bearing bores. Replace the
crankcase assembly if a bearing bore is galled or if
bearing inserts have rotated in the case.
4. Be sure alignment pins are in place where used.
5. Refer to "Oil Flow Chart" at the beginning of this
chapter and trace the oil paths through the
crankcase and cylinder.
6. Flush all oil passages with solvent and then warm
soapy water. Rinse with clear, warm water and dry
with compressed air.
7. Be sure passages are clean and dry before
assembling the upper crankcase.
3.70
CRANKSHAFT
G
Blue Green
Green Yellow
Yellow Yellow

PISTON RING INSTALLATION

Apply clean engine oil to all ring surfaces and ring lands
Y
upon installation. Always check piston ring installed gap
before rings are installed on piston (see Chapter 3 –
Piston Ring Installed Gap page 3.66. Clean
accumulated carbon from piston ring grooves and oil
ring lube holes if piston has been in service.
q
Top Ring
w
Second Ring
e
Upper Rail
1. Place oil control ring expander in oil ring groove.
Rotate expander in groove until butt ends are on
PTO side of piston
Ends must butt squarely together and must not overlap.
2. Install lower rail with end gap positioned on the
intake side of piston
3. Install upper rail with end gap positioned on the
exhaust side of piston
NOTICE
r
Spring Expander
t
Lower Rail
r
.
NOTICE
t
.
e
.
9929422 R02 - 2017-2019 ACE 900 Service Manual
© Copyright Polaris Industries Inc.