Snowmobile Polaris EDGE / WIDETRAK (2007-2012 year). Manual - part 27

5.6

Engine Systems

9923396 - 2007-2012 EDGE/Widetrak LX Service Manual

any up and down movement detectable in the big end
bearing.

Piston Needle Bearing

Clean the end of the connecting rod and inspect inner
bore with a magnifying glass. Look for any surface
irregularities including pitting, wear, or dents.

Run a fingernail around the inside of the rod and check
for rough spots, galling, or wear.

Oil and install needle bearing and pin in connecting
rod.

Rotate pin slowly and check for rough spots or any
resistance to movement.

Slide pin back and forth through bearing while rotating
and check for rough spots.

With pin and bearing centered in rod, twist ends back
and forth in all directions to check for excessive axial
play.

Pull up and down evenly on both ends of pin to check
for radial play.

Replace pin and bearing if there is any resistance to
rotation or excessive axial or radial movement. If play
or roughness is evident with a new pin and bearing,
replace the connecting rod.

Crankshaft Index

Polaris crankshafts are pressed together. The connecting
rod journal center lines are indexed 180° apart from each
other.

It is sometimes necessary to check multi-cylinder
crankshafts to verify that one cylinder has not been forced
out of position relative to the other cylinder. Some causes
for a “out of index” crankshaft include but are not limited to
the following:

• Hydrolock from water or fuel

• Impact to drive clutch from object or accident

• Abrupt piston or other mechanical failure

• Engine lock-up due to drive belt failure

Symptoms of an out of index crankshaft can include but
are not limited to the following:

• Difficulty calibrating carburetor (repetitive plug

fouling on one cylinder with no other cause)

• Unexplained piston failure on one cylinder (i.e.

severe detonation, broken ring lands, etc.)

• Excessive vibration of engine, back-firing, etc.

• Rough idle, poor top speed.

5.7

Engine Systems

9923396 - 2007-2012 EDGE/Widetrak LX Service Manual

Checking Crankshaft Index

Remove the drive belt and drive clutch.

Securely fasten a large degree wheel on the flywheel
or PTO end of the crankshaft. Make sure that it is
mounted concentrically with the crankshaft center
line.

With a section of wire (wire coat hanger), anchor it to
a convenient spot. Bend one end at the outer
perimeter of the degree wheel as shown below.

Install a dial indicator into the magneto end cylinder
spark plug hole. The ignition timing is referenced by
the magneto end.

Locate TDC as accurately as possible by finding the
center of the point where there is no piston movement
note the “Zero” the dial indicator at this point.

Continue to rotate the crankshaft in the normal
direction of rotation until the dial indicator reads .100"
(2.54mm) after top dead center (ATDC).

Bend the pointer or move the degree wheel until the
pointer aligns with a 180° mark on the degree wheel.

With the pointer aligned, make sure the degree wheel
and pointer are secured and will not move out of
position. Re-check accuracy of this location a few
times. The pointer should align with the 180° mark
when the dial indicator reads .100” (2.54mm) ATDC.

NOTE: Do not move the crankshaft, degree wheel or
pointer after the initial setting on the MAG end
cylinder - simply read the wheel and dial indicator.

Remove the dial indicator and install in PTO cylinder.
Repeat finding TDC process. Note the degree wheel
indication when the dial indicator reads .100" ATDC.
It should be 180° (+/-2°) from the MAG cylinder mark.

5.8

Engine Systems

9923396 - 2007-2012 EDGE/Widetrak LX Service Manual

Cylinder Honing

The cylinder bore must be de-glazed whenever new piston
rings are installed. A light honing with fine stones removes
only a very small amount of material. A proper crosshatch
pattern is important to provide a surface that will hold oil,
and allow the rings to seat properly. If the crosshatch is too
steep, oil retention will be reduced. A crosshatch angle
which is too shallow will cause ring vibration, poor sealing,
and overheating of the rings due to blow-by and reduced
contact with the cylinder wall. Service life of the pistons
and rings will be greatly reduced.

NOTE: A Nicasil cylinder can be lightly honed with a
320 grit stone hone but can not be oversized.

Honing Tools

The following tools are recommended:

• Ammco 3950 Hone Kit - SPX PN: 2870303

• Honing Oil - SPX PN: 2870588

• Oversize 320 grit stone (69.8 - 92.8mm) - SPX PN:

PU-49876

Honing Procedure

Wash the cylinder with cleaning solvent.

Clamp the cylinder in a soft jawed vise by the cylinder
studs.

Place hone in cylinder and tighten stone adjusting
knob until stone contacts the cylinder walls (DO NOT
OVERTIGHTEN).

Apply honing oil to the stones and cylinder walls. Wet
honing removes more material faster and leaves a
more distinct pattern in the bore.

Using a 1/2" (13 mm) drill motor rotating at a speed of
300-500 RPM, run the hone in and out of the cylinder
rapidly until cutting tension decreases. Remember to

keep the hone driveshaft centered to prevent edge
loading and always bring the stone approximately 1/
2" (1.2 cm) beyond the bore at the end of each stroke.

Release the hone at regular intervals to inspect bore
size and finish.

Honing To Oversize (Iron-Lined Cylinders)

If cylinder wear or damage is excessive, it will be
necessary to oversize the cylinder using a new oversize
piston and rings. This may be accomplished by either
boring the cylinder and then finish honing to the final bore
size, or by rough honing followed by finish honing.

For oversize honing always wet hone using honing oil and
a coarse roughing stone. Measure the new piston at room
temperature (see piston measurement) and rough hone to
the size of the piston or slightly larger. Always leave .002"
- .003" (.05 - .07 mm) for finish honing. Complete the sizing
with fine grit stones to provide the proper cross-hatch
finish and required piston clearance.

Inspect cylinder for taper and out-of-round. Taper or out-
of-round on the finished bore should not exceed .0004"
(.002mm).

NOTE: Portable rigid hones are not recommended for
oversizing cylinders, cylinder boring, and finish
honing. The use of an arbor type honing machine is
recommended. Always check piston to cylinder
clearance and piston ring installed gap after boring /
honing is complete.

Cleaning The Cylinder After Honing

It is very important that the cylinder be thoroughly cleaned
after honing to remove all grit material. Wash the cylinder
in a solvent, then in hot soapy water. Pay close attention
to areas where the cylinder sleeve meets the aluminum
casting (transfer port area). Use electrical contact cleaner
if necessary to clean these areas. Rinse thoroughly, dry
with compressed air, and oil the bore immediately with
Polaris Premium 2 Cycle Lubricant.

NOTE: Always check piston to cylinder clearance
and piston ring installed gap after honing or boring is
complete.

EXAMPLE OF A CROSS HATCH PATTERN

5.9

Engine Systems

9923396 - 2007-2012 EDGE/Widetrak LX Service Manual

Crankshaft Truing

Lubricate the bearings and clamp the crankshaft securely
in the holding fixture. If truing the crankshaft requires
striking with a hammer, always be sure to re-check
previously straightened areas to verify truing. Refer to the

illustrations below. Use Crankshaft alignment kit PN
2870569.

NOTE: The Rod Pin position in relation to the dial
indicator tells you what action is required to
straighten the shaft.

Truing Examples

To correct a situation like this. Strike the shaft at
point A with a brass hammer.

To correct a situation like the one shown in this.
Squeeze the crankshaft at point A. You will use the
tool from the alignment kit PN 2870569.

If the crank rod pin location is 180° from the dial
indicator (opposite of above), it will be necessary to
spread the crankshaft at the A position as shown in
illustration 3. When rebuilding and straightening a
crankshaft, straightness is of utmost importance.
Runout must be as close to zero as possible.

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