Snowmobile Arctic Cat (2002 year). Manual - part 16

2-47

2

AQ029

23. Before lifting the cylinder base gasket from the

crankcase, note how it is installed. The smaller of

the three water passage holes must be positioned

to the MAG-side of the crankcase when installing.

Lift the gasket free of the crankcase.

„

NOTE: If the cylinder base gasket is not dam-

aged, it can be reused.

AQ030

24. Remove the two screws securing the oil-injection

pump to the crankcase. Slide the pump free of the

crankcase. Account for the O-ring located around

the pump inner flange.

25. Remove the pump retainer and shaft. Account for

the shaft thrust washer.

AQ119

26. Remove the six cap screws securing the intake

flanges and reed valve assembly to the crankcase.

27. Remove each intake flange and reed valve

assembly. Be very careful not to damage the reed

valve stops. Place the assembly on its flat side.

Remove and discard the reed valve assembly

gasket.

AN236

28. Using an impact driver, remove the four screws

securing the PTO-end plate to the end of the

crankcase; then slide the plate free of the

crankshaft.

AQ034

29. Remove the twenty cap screws securing the two

crankcase halves together.

AQ035

30. To separate the crankcase halves, start two of the

crankcase cap screws into the crankcase at

opposite corners. Thread the cap screws into the

crankcase until a 6.4 mm (1/4 in.) space remains

between the cap screw flange and the crankcase

surface.

2-48

AQ036

31. Set the crankcase on its side with the flat reed

surfaces resting on the work bench. Using a plastic

hammer, strike the heads of the two cap screws

alternately driving the two case halves apart.

32. Once there is a 6.4 mm (1/4 in.) space between the

two case halves, set the crankcase down on the

work bench with its bottom side up. Remove the

cap screws; then lift the bottom of the crankcase

free of the engine. Account for the two dowel pins.

AQ037

33. Remove the balancer shaft from the crankcase.

Notice that it has a timing mark located on the side

of the drive gear. This timing mark must be

aligned with the crankshaft gear during assembly.

AQ038

34. Remove the balancer shaft end seals from the

crankcase.

35. Grasp the crankshaft at either end and carefully lift

it from the crankcase. Have a clean area ready to

lay the crankshaft on once it has been removed.

AQ039

36. With the crankshaft removed from the top half of

the crankcase, remove the seven bearing retaining

pins and the two C-rings.

AQ040

Servicing Components

(120 cc)

Thoroughly clean all non-electrical components in

parts-cleaning solvent; then remove any carbon

buildup from the cylinder head, piston dome, valves,

and valve seats.

Visually inspect all engine components for wear or

damage.

„

NOTE: Whenever a part is worn excessively,

cracked, or damaged in any way, replacement is
necessary.

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2

CYLINDER HEAD/VALVE ASSEMBLY

„

NOTE: Remove the valves by pressing down on

the spring retainer and removing the valve keeper.
Account for valve springs, spring retainers, and
valve keepers.

When servicing valve assembly, inspect valve seats,

valve stems, valve faces, and valve stem ends for pits,

burn marks, or other signs of abnormal wear.

„

NOTE: Discard any valve that fails the listed

inspections. Do not grind the valves. If a valve is
damaged, it must be replaced.

Measuring Cylinder Head Distortion

1. Using a non-metallic carbon removal tool, remove

any carbon buildup from the combustion chambers

being careful not to nick, scrape, or damage the

combustion chambers or the sealing surfaces.

2. Inspect the spark-plug holes for any damaged

threads. Repair damaged threads using a heli-coil

insert.

3. Inspect the cylinder head for flatness using a

straightedge and a feeler gauge. Acceptable

distortion must not exceed 0.03 mm (0.0012 in.).

„

NOTE: If the distortion exceeds specification,

replace the cylinder head.

Measuring Valve Stem Runout

1. Support each valve stem end with V Blocks (p/n

0644-022); then check the valve stem runout using

a dial indicator.

ATV-1082

2. Maximum runout is 0.05 mm (0.002 in.) for both

valves.

Measuring Valve Face Width

1. Using a micrometer, measure the width of the

valve face.

ATV-1004

2. Acceptable valve face width must be within a

range of 0.8-1.0 mm (0.032-0.039 in.).

Measuring Valve Face Runout

1. Mount a dial indicator on a surface plate; then

place the valve stem on a set of V blocks.

2. Position the dial indicator contact point on the

outside edge of the valve face; then zero the

indicator.

ATV1082A

3. Rotate the valve in the V blocks.

4. Maximum runout is 0.03 mm (0.0012 in.).

Replacing Valve Guide

„

NOTE: If a valve guide is worn or damaged, it

must be replaced.

1. If a valve guide needs replacing, before removing

the existing guide, measure the distance from the

top of the valve seat to the top of the valve guide

(B) for a reference depth when installing the new

guide.

2-50

GEN-0021

2. To replace a valve guide, use a valve guide

remover from the top side of the cylinder to gently

pull the valve guide out of the cylinder.

GEN-0017

3. Using a valve guide reamer, remove any burrs or

tight areas from the valve guide journals.

GEN-0018

4. Valve guide hole diameter (after reaming) intake

and exhaust must be within a range of 11.200-

11.218 mm (0.4409-0.4416 in.).

5. To install an oversized valve guide at room

temperature, use a valve guide installer and gently

drive a valve guide into the bore from the top side

until the guide is set to the distance noted before

removal.

„

NOTE: Install the valve guide so the stepped part

on the guide wall faces the head of the valve.

GEN-0019

GEN-0020

6. After installing the guide, measure the inside

diameter of the guide. The measurement must be

within a range of 5.500-5.512 mm (0.2165-

0.2170 in.). If the measurement does not fall

within the specification or the valve does not move

freely in the guide, use a standard valve guide

reamer and handle to remove all burrs and tight

areas that may remain in each valve guide.

GEN-0022