Snowmobile Polaris EDGE / WIDETRAK (2007-2012 year). Manual - part 26

5.2

Engine Systems

9923396 - 2007-2012 EDGE/Widetrak LX Service Manual

©2011 Polaris Sales Inc.

ENGINE TORQUE SEQUENCES

Crankcase Torque Patterns

340 Engine

550 Engine

488 Engine

500EV Engine

Cylinder Torque Patterns

340 / 550 / 500EV Engines

488 Engine

Cylinder Head Torque Patterns

340 Engine

550 Engine

PTO

MAG

1

2

3

4

5

6

7

8

9

10

11

12

PTO

MAG

1

2

3

4

5

6

7

8

9

10

11

12

13

14

PTO

MAG

1

2

3

4

5

6

7

8

9

10

11

12

MAG

PTO

PTO

MAG

1

2

3

4

PTO

MAG

4

2

2

5

6

1

7

PTO

MAG

1

2

3

4

PTO

MAG

1

2

3

4

5

6

7

8

9

10

11

12

5.3

Engine Systems

5

9923396 - 2007-2012 EDGE/Widetrak LX Service Manual

©2011 Polaris Sales Inc.

488 Engine

500EV Engine

ENGINE INSPECTIONS

Cylinder Head Inspection

Using a flat bar and a feeler gauge, inspect each cylinder
head for warping. Replace head if warping exceeds .003"
(.08mm).

Cylinder Measurement

Inspect each cylinder for wear, scratches, or damage. If no
damage is evident, measure the cylinder for taper and out
of round with a telescoping gauge or a dial bore gauge.
Measure the bore 1/2" from the top of the cylinder; in line
with the piston pin and 90° to the pin to determine if the
bore is out of round. Repeat the measurements at the
middle and bottom of the cylinder. Use the chart below and
record all measurements.

= In. / mm. 

Cylinder Head Warp Limit

.003" (.08mm)

P

M

2

3

4

6

8

12

13

9

10

14

11

7

5

1

MAG

PTO

Cylinder Measurement Worksheet

TOP

X

Y

MIDDLE

X

Y

BOTTOM

X

Y

Out-of-Round = Top X - Top Y and Bottom Y - Bottom X

Taper = Top Y - Bottom Y and Top X - Bottom X

5.4

Engine Systems

9923396 - 2007-2012 EDGE/Widetrak LX Service Manual

©2011 Polaris Sales Inc.

Crankshaft Runout Inspection

1.

Support the crankshaft in a set of “V” blocks as shown.

2.

Use a dial indicator to measure the runout at the
following locations:

• PTO end = First taper after bearing flat.

• MAG end = 1/2" from bearing flat.

3.

Runout deflection cannot exceed .0025" (.07mm).

4.

If the runout deflection exceeds the maximum
specification, crankshaft trueing may correct the
deflection.

Piston Inspection

Check piston for scoring or cracks in piston crown or pin
area. Excessive carbon buildup below the ring lands is an
indication of piston, ring or cylinder wear. On Fuji engines,
measure piston outside diameter at a point that is 1/2"
(12.7mm) up form the bottom of the skirt at a 90° angle to
the direction of the piston pin.

Subtract this measurement from the minimum cylinder
measurement (90° to the pin). If clearance exceeds the
service limit, the cylinder should be re-bored (replaced if
Nicasil-lined) and new pistons and rings installed.

= In. / mm. 

Taper Limit = .002" (.051mm)

Out-of-Round Limit = .002" (.051mm)

5.5

Engine Systems

5

9923396 - 2007-2012 EDGE/Widetrak LX Service Manual

©2011 Polaris Sales Inc.

Piston Ring Installed Gap

Position the ring 1/2" (1.3 cm) from the top of the cylinder
using the piston to push it squarely into place. Measure
installed gap with a feeler gauge at both the top and
bottom of the cylinder.

NOTE: A difference in end gap indicates cylinder
taper. The cylinder should be measured for excessive
taper and out-of-round. Replace rings if the installed
end gap exceeds the service limit. Always check
piston ring installed gap after re-boring a cylinder or
when installing new rings.

Piston rings are installed with marking or beveled side up.

Bearing Fit

Any time crankshaft bearing failure occurs and the case is
reused, check the bearing fit into the case halves using the
following procedure.

With case halves cleaned, press a replacement bearing
into each of the main bearing journals to determine a basic
amount of press fit.

Do a comparison check of all journals by manually forcing
the bearing into the bearing seats noting if any are
noticeably loose or tight. Normal hand installation will be
an indication of the recommended interference fit. If the
bearing falls out of the case when the case is inverted, or
if the crankcase bearing surface is severely galled or
damaged, the crankcase assembly should be replaced.

Main Bearing

Clean crankshaft thoroughly and oil main and connecting
rod bearings with Polaris engine oil. Carefully check each
main bearing on the crankshaft.

Due to extremely close tolerances, the bearings must be
inspected visually and by feel. Look for signs of
discoloration, scoring or galling. Turn the outer race of
each bearing. The bearings should turn smoothly and
quietly. The inner race of each bearing should fit tightly on
the crankshaft. The outer race should be firm with minimal
side to side movement and no detectable up and down
movement. Replace any loose or rough bearings.

Connecting Rod Lower Bearing

Measure connecting rod big end side clearance with a
feeler gauge on both sides of the connecting rod. The side
clearance on either side of the connecting rod cannot
exceed the connecting rod side clearance specification.
The difference between the two clearance measurements
cannot exceed the maximum clearance differential
specification.

Rotate the connecting rod on the crankshaft and feel for
any rough spots. Check radial end play in rod by
supporting rod against one thrust washer and alternately
applying up and down pressure. Replace bearing, pin, and
thrust washers if side clearance is excessive or if there is

= In. / mm. 

Bearing Interference Fit: .001-.002" (.026-.051mm)

= In. / mm. 

Connecting Rod Side Clearance: 

.012"-.016" (.30-.40mm)

Maximum Clearance Differential

.002" (.051mm)