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Snowmobile Polaris 2006 - 2007 FS / FST. Manual - part 37

6.39

FS / FST Engine

Rev. 1 07/2006

Crankshaft Main Bearing Oil Clearance

Inspection

NOTE:

Do not move the crankshaft until the

measurement process is completed. Do not place
Plastigauge strips over oil holes in crank pins.

Replace the main bearings into the upper crankcase as they
were positioned prior to removal.

Install the crankshaft. Install a piece of Plastigauge across
each journal surface.

Install the lower crankcase with the main bearings already
installed.

Loosely install the four lower crankcase fasteners.

Rotate the engine assembly on the engine stand. Install the
original head gasket.

Install the cylinder head and nuts.

Torque the nuts and lower fasteners to specifications as
outlined within this chapter.

Carefully disassemble the engine. Do not allow the
crankshaft to rotate.

Measure each piece of compressed Plastigauge at its widest
point and record.

10. Follow the Bearing Replacement Guide

Bearing Replacement Guide

NOTE: The color code is imprinted on the side of
each bearing shell.

• Crankshaft Main Bearing Oil Clearance Specification:

.05 - .06mm (.002 - .0023in.)

• Measured Oil

Clearance:____________________________

• Original Bearing Color /

Thickness:___________________________

REPLACEMENT BEARINGS (THICKNESS RANGE):

• RED (0451343): 1.990 - 1.995mm (.0783 - .0785in.)

• YELLOW (0451342): 1.995 - 2.000mm (.0785 -

.0787in.)

• BLUE (0451344): 2.000 - 2.005mm (.0787 - .0789in.)

• GREEN (0451345): 2.005 - 2.010mm (.0789 -

.0791in.)

If the measured clearance is within specifications, replace
bearings with new bearings with the same color code.

If the measured gap is larger than specified, replace bearings
with the next larger bearing and re-measure.

If the measured gap is smaller than specified, replace bearings
with the next smaller bearing and re-measure.

Always measure the crankcase main bearing and connecting rod
big-end inside diameters and compare to specifications. Replace
components that are outside of specification.

If the original bearings reveal an oil clearance of .04 - .05mm,
install new bearings with the same color code as the originals.

6.40

FS / FST Engine

Rev. 1 07/2006

Crankcase / Crank Train / Piston Assembly

Position the upper crankcase as shown in the photo.

Prepare each piston assembly for installation into the
crankcase. Lubricate each piston assembly with engine oil.

Place the piston installation tool, PN PW-46983, over one
of the piston bores. Lubricate the inner diameter of the tool
with engine oil.

Position one piston assembly inside the tool and align each
ring end gap as illustrated.

Install the piston assembly into the installation tool. Verify
the piston pin c-clip eye is facing towards the INTAKE-
SIDE of the engine. The piston pin boss edge faces the
EXHAUST-SIDE of the engine.

Carefully press the piston assembly into the cylinder bore.

Repeat process to install the second piston assembly. Wipe
up any excess oil leftover from the piston installation
process.

Position the upper crankcase as shown in the photo. Clean
each bearing journal.

Lubricate each bearing journal with engine oil.

10. Install a new set of balance shaft bearings into the

crankcase. Lubricate bearings with engine oil.

11. Install each crankshaft main bearing into the crankcase.

Lubricate each bearing with engine oil.

12. Install each connecting rod bearing. Lubricate each bearing

with engine oil.

13. Install the pivoting chain guide. Torque fastener to

specification.

14. Install the crankshaft and balance shaft at the same time.

NOTE: The balance shaft drive gear must be at least
loosely installed prior to installing the balance shaft
in to the crankcase.

15. Align the timing dot on the balance shaft gear with the

timing dot on the crankshaft gear.

PISTON RING END-GAP

6.41

FS / FST Engine

Rev. 1 07/2006

16. Carefully push each piston assembly towards the

crankshaft and seat the connecting rods against the
crankshaft journals.

17. Verify the correct bearings are installed in each of the two

connecting rod caps. Lubricate each bearing and crankshaft
journal with engine oil.

18. Match each rod caps unique “cracked” mating surface with

the matching connecting rod.

19. Loosely install the rod cap fasteners, then tighten evenly.

20. Torque fasteners to specifications.

21. Obtain the lower crankcase. Remove any foreign material

and sealant from the mating and bearing surfaces. Install the
balance shaft and crankshaft bearings into the crankcase.
Verify each bearing is its correct location when matched to
the upper crankcase bearings. Lubricate each bearing with
engine oil.

22. Apply a thin bead of Three bond 1215 sealant as

represented by the black line in the photo.

23. Verify the four plastic oil control stud jackets are installed

in the middle of each stud.

24. Carefully lower the lower crankcase on to the upper

crankcase.

25. Loosely install the two middle lower crankcase fasteners to

keep the crankcases from separated when the engine is
rotated.

26. Rotate the engine so the cylinder head is pointed upwards.

27. Clean the cylinder head gasket mating surface.

28. Install a new cylinder head gasket making sure the writing

on the gasket is visible, the small cooling passages are on
the intake-side (starter motor side) of the engine and the
large cooling passages are on the exhaust-side of the
engine.

29. Install the fixed chain guide into the cylinder head. Torque

fastener to specification.

30. Install the cylinder head assembly. Install each cylinder

head nut and tighten securely.

SLEEVE

STUD

LWR CRANKCASE

(PATTERN)

LARGE PASSAGES

6.42

FS / FST Engine

Rev. 1 07/2006

31. With the cylinder head secured to the crankcase, rotate the

engine so the cylinder head is pointed down.

32. Install the oil pressure relief piston, guide pin, and spring

into the fastener bore. Insert the fastener with the relief
clamp over the guide pin. Tighten the fastener, then install
the remaining lower crankcase fastener.

33. Perform the five-step torque sequence procedure for

tightening the cylinder head nuts and lower crank case
fasteners. The sequence and torque values are outlined in
the torque specification table and sequence illustration at
the beginning of this chapter.

34. Rotate the engine to gain access to the PTO shaft. Slide the

crank seal installation tool over the PTO shaft. Apply a light
film of oil to the surface of the tool. Install the crankshaft
seal by carefully tapping around the outside circumference
of the seal.

35. The following procedures must be completed to finish the

re-assembly process:

• Timing Chain Installation / Locating TDC

• Valve Cover Installation

• Sump / Bedplate Installation

• Water Pump / Pump Components / Thermostat

Manifold Installation

• Gear Cover / Flywheel / Alternator Assembly

Installation

• Cylinder Head / Timing Chain / Chain Tensioner

Installation

• Starter Motor Installation

• High Pressure Oil Pump Assembly Installation

• Valve Lash Adjustment

Timing Chain Installation / Locating TDC

Timing chain installation requires setting the pistons to TDC
(Top Dead Center).

The pistons are at TDC when the set of SINGLE timing marks
are aligned with each other, and the set of DOUBLE timing
marks are aligned with the upper and lower crankcase parting
line.

Install the timing chain installation tool, PN PW-47079,
into the lower crankcase.

DOUBLE

SINGLE TIMING

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