ATV Arctic Cat 2002. Service Manual - part 14

6

3

77)

32. If removed, install the spark plug. Tighten to 1.7

kg-m (12 ft-lb).

Installing 

Engine/Transmission

(375/500 Automatic)

„

 

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1. From the right side, place the engine/transmission

into the frame making sure it is properly

positioned in the frame with the front and rear

driveshafts properly aligned.

2. Slightly raise the front of the engine and insert the

front driveshaft coupler.

58?

3. Position the two upper rear engine mounts in place

on the frame and loosely secure with existing

hardware; then install the three engine mounting

through-bolts making sure to account for a washer

on the upper bolt and a spacer on the lower front

bolt. Tighten only until snug.

4. Align the front and rear driveshafts and secure

with existing hardware. Tighten only until snug.

5. Secure the front upper engine mount to the frame

with the cap screws. Tighten to 2.8 kg-m (20 ft-lb).

6. Secure the upper engine bracket to the engine with

the existing cap screw and flange nut. Tighten to

2.8 kg-m (20 ft-lb).

7. Tighten all engine mounting through-bolts to 5.5

kg-m (40 ft-lb); then tighten the cap screws

securing the rear CV joint to 2.8 kg-m (20 ft-lb).

Tighten the front driveshaft to 5.5 kg-m (40 ft-lb);

then tighten the two upper rear engine mounts to

1.7 kg-m (12 ft-lb).

565

566

8. Secure the exhaust pipe to the engine, frame, and

muffler using existing hardware. The cap screws

securing the exhaust pipe to the engine and to the

frame should be tightened to 2.8 kg-m (20 ft-lb).

9. Install the left-side clutch plenum with existing

hardware making sure the gasket is properly

positioned. Tighten securely.

589

RepairPro Service Manual

6

10. Secure the engine ground wire to the engine with a

cap screw. Tighten to 1.1 kg-m (8 ft-lb).

11. Install the shift indicator connector to the main

wiring harness.

58

12. Connect the temperature sensor wire(s) to the

engine.

„

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58

13. Secure the stator wires to the CDI unit.

569

14. Secure the speedometer cable to the speedometer

gear housing.

56?

15. Secure the positive cable to the starter motor.

16. Secure all wiring to the frame and upper engine

bracket with cable ties.

17. Secure the two coolant/oil hoses to the engine.

18. Secure the crankcase vent hose to the air cleaner

housing.

19. Secure the shift rod to the engine with a new

E-clip; then secure the shift rod to the shift lever

arm with a new lock nut. Tighten securely.

/94

20. Install the exhaust pipe cover and secure with the

existing torx-head screws. Tighten securely.

6

3

567

21. Install the carburetor into the intake hose. Tighten

the hose clamp.

22. Place the footrests in position on the frame; then

secure with existing hardware. Tighten the 10 mm

cap screws to 5.5 kg-m (40 ft-lb) and the 8 mm cap

screws to 2.8 kg-m (20 ft-lb).

23. Secure the fender extensions to the footrest using

existing hardware.

24. Install the cooling duct shroud; then secure the

cooling duct assembly to the frame.

/9

/9?

25. Install the air cleaner housing and secure the air

intake hose to the carburetor; then secure the

crankcase vent hose to the air cleaner housing.

56

26. Install the rear rack/fender assembly with existing

hardware. Tighten securely.

27. Connect the taillight wiring harness to the main

harness and secure with cable ties.

28. Install the gas tank; then connect the vent hose.

54

29. Connect the fuel hose to the gas tank valve.

5

30. Install the left-side and right-side panels.

31. Place the battery into position in the battery

compartment; then install the battery cables and

vent hose. Secure with the hold-down strap.

! CAUTION

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RepairPro Service Manual

64

32. Add proper amounts of engine/transmission oil

and coolant.

33. Install the seat.

Table of Contents

(Servicing Components)

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Servicing Top-Side 

Components

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VALVE ASSEMBLY

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.

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Cleaning/Inspecting Valve Cover

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1. Wash the valve cover in parts-cleaning solvent.

2. Place the valve cover on the Surface Plate (p/n

0644-016) covered with #400 grit wet-or-dry

sandpaper. Using light pressure, move the valve

cover in a figure eight motion. Inspect the sealing

surface for any indication of high spots. A high

spot can be noted by a bright metallic finish.

Correct any high spots before assembly by

continuing to move the valve cover in a figure

eight motion until a uniform bright metallic finish

is attained.

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7)

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Removing Valves

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1. Using a valve spring compressor, compress the

valve springs and remove the valve cotters.

Account for an upper spring retainer.

9)

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2. Remove the valve seal and the lower remaining

spring seat. Discard the valve seal.

4)

6)

„

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3. Remove the valve springs; then invert the cylinder

head and remove the valves.

Measuring Valve Stem Runout

1. Support each valve stem end with the V Blocks

(p/n 0644-022); then check the valve stem runout

using a dial indicator.

'7?

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

Measuring Valve Stem 
Outside Diameter

1. Using a micrometer, measure the valve stem

outside diameter.

2. Acceptable diameter range (intake valve) is

5.475-5.490 mm (0.2156-0.2161 in.) for the

250/300 and 4.975 - 4.990 mm (0.1959 - 0.1965

in.) for the 375/400/500.

3. Acceptable diameter range (exhaust valve) is

5.455-5.470 mm (0.2148-0.2154 in.) for the

250/300 and 4.955 - 4.970 mm (0.1951 - 0.1957

in.) for the 375/400/500.

Measuring Valve Face/Seat Width

1. Using a micrometer, measure the width of the

valve face.

RepairPro Service Manual

66

'774

2. Acceptable width range is 0.9-1.1 mm

(0.035-0.043 in.).

Measuring Valve Face Radial 
Runout

1. Mount a dial indicator on the 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.

'7?

3. Rotate the valve in the V blocks.

4. Maximum runout is 0.03 mm (0.001 in.).

Measuring Valve Guide/Valve Stem 
Deflection (Wobble Method)

1. Mount a dial indicator and base on the surface

plate; then place the cylinder head on the surface

plate.

2. Install the valve into the cylinder head; then

position the dial indicator contact point against the

outside edge of the valve face. Zero the indicator.

)

3. Push the valve from side to side; then from top to

bottom.

4. Maximum “wobble” deflection is 0.35 mm (0.014

in.).

Measuring Valve Guide
(Inside Diameter)

1. Insert a snap gauge 1/2 way down into each valve

guide bore; then remove the gauge and measure it

with a micrometer.

2. Acceptable inside diameter range is 5.500-5.512

mm (0.2165-0.2170 in.) for the 250/300 and 5.000

- 5.012 mm (0.1969 - 0.1973 in.) for the

375/400/500.

3. If a valve guide is out of tolerance, it must be

replaced.

Replacing Valve Guide

„

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1. If a valve guide needs replacing, insert a valve

guide remover into the valve seat side of the valve

guide. Using a hammer, gently drive the valve

guide out of the cylinder head.

9)

68

3

8)

2. Using the Standard Valve Guide Reamer (p/n

0444-017), remove any burrs or tight areas from

the valve guide journals.

4)

3. To install a valve guide, use a valve guide installer

and gently drive a valve guide with a retaining clip

into the bore from the valve spring side until the

retaining clip just contacts the cylinder head.

4)

4. After installing the guide, use the standard valve

guide reamer to remove all burrs and tight areas

that may remain in each valve guide.

94)

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Valve Seat/Guide Servicing Flow 
Chart

'778

RepairPro Service Manual

6?

Grinding Valve Seats

„

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1. Insert an exhaust valve seat pilot shaft into an

exhaust valve guide. Slide an exhaust valve seat

grinding tool onto the pilot shaft; then using light

pressure on a driver handle and a deep socket,

grind the exhaust valve seat until within

specifications.

96)

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9)

2. Insert an intake valve seat pilot shaft into one of

the intake valve guides. Slide the intake valve seat

grinding tool onto the pilot shaft; then using light

pressure on a driver handle and a deep socket,

grind the intake valve seat until within

specifications.

95)

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47)

Lapping Valves

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1. Remove all carbon from the valves.

2. Lubricate each valve stem with light oil; then

apply a small amount of valve lapping compound

to the entire seating face of each valve.

3. Attach the suction cup of a valve lapping tool to

the head of the valve.

4. Rotate the valve until the valve and seat are evenly

polished.

5. Clean all compound residue from the valve and

seat.

Measuring Rocker Arm
(Inside Diameter)

1. Using a dial calipers, measure the inside diameter

of the rocker arm.

2. Acceptable inside diameter range is 12.000-12.018

mm (0.472-0.473 in.).

Measuring Rocker Arm Shaft 
(Outside Diameter)

1. Using a micrometer, measure the outside diameter

of the rocker arm shaft.

2. Acceptable outside diameter range is

11.977-11.995 mm (0.4715-0.4722 in.) for the

250/300 and 11.973-11.984 mm (0.4714-0.4718

in.) for the 375/400/500.

Installing Valves

1. Apply grease to the inside surface of the valve

seals; then place a lower spring seat and valve

guide seal over each valve guide.

69

3

44)

2. Insert each valve into its original valve location.

3. Install the valve springs with the painted end of the

spring facing away from the cylinder head.

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4. Place a spring retainer over the valve springs; then

using the valve spring compressor, compress the

valve springs and install the valve cotters.

9)

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PISTON ASSEMBLY

„

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Cleaning/Inspecting Piston

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

any carbon buildup from the dome of the piston.

2. Inspect the piston for cracks in the piston pin,

dome, and skirt areas.

3. Inspect the piston for seizure marks or scuffing.

Repair with #400 grit wet-or-dry sandpaper and

water or honing oil.

5

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4. Inspect the perimeter of each piston for signs of

excessive “blowby.” Excessive “blowby” indicates

worn piston rings or an out-of-round cylinder.

Removing Piston Rings

1. Starting with the top ring, slide one end of the ring

out of the ring-groove.

RepairPro Service Manual

87

477)

2. Remove each ring by working it toward the dome

of the piston while rotating it out of the groove.

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Cleaning/Inspecting Piston Rings

1. Take an old piston ring and snap it into two pieces;

then grind the end of the old ring to a 45° angle

and to a sharp edge.

2. Using the sharpened ring as a tool, clean carbon

from the ring-grooves. Be sure to position the ring

with its tapered side up.

Measuring Piston-Ring End Gap
(Installed)

1. Place each piston ring in the wear portion of the

cylinder. Use the piston to position each ring

squarely in the cylinder.

2. Using a feeler gauge, measure each piston-ring

end gap. Acceptable ring end gap must be a

maximum 0.70 mm (0.0276 in.) 1st ring and 1.0

mm (0.039 in.) 2nd ring for the 250/300, a

maximum 0.50 mm (0.020 in.) both rings for the

375/400, and a maximum 0.70 mm (0.0276 in.)

both rings for the 500.

?6)

?7)

Measuring Piston Pin (Outside 
Diameter) and Piston-Pin Bore

1. Measure the piston pin outside diameter at each

end and in the center. If measurement is less than

16.98 mm (0.6685 in.) for the 250/300, 19.98 mm

(0.787 in.) for the 375, 20.98 mm (0.826 in.) for

the 400, and 22.98 mm (0.905 in.) for the 500, the

piston pin must be replaced.

'787

2. Insert an inside dial indicator into the piston-pin

bore. The diameter must be a maximum 17.03 mm

(0.6705 in.) for the 250/300, 20.03 mm (0.789 in.)

for the 375, 21.03 mm (0.828 in.) for the 400, and

23.03 mm (0.907 in.) for the 500. Take two

measurements to ensure accuracy.

! CAUTION

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8

3

'769

Measuring Piston Skirt/
Cylinder Clearance

1. Measure the cylinder front to back in six places.

98)

2. Measure the corresponding piston diameter at a

point 18 mm (0.71 in.) for the 250/300 and 15 mm

(0.6 in.) for the 375/400/500 above the piston skirt

at a right angle to the piston-pin bore. Subtract this

measurement from the measurement in step 1. The

difference (clearance) must be a maximum 0.12

mm (0.0047 in.) for the 250/300 and within a

range of 0.065-0.075 mm (0.0026-0.0030 in.) for

the 375, 0.045-0.120 mm (0.0018-0.0047 in.) for

the 400, or 0.038-0.076 mm (0.0015-0.0030 in.)

for the 500.

Installing Piston Rings

1. Install a thin ring, corrugated ring, and thin ring in

the bottom groove of the piston. Stagger the gaps

of the upper and lower thin rings.

'7?5

2. Install the middle and upper rings so the letter on

the top surface of each ring faces the dome of the

piston. Rotate the rings until the ring gaps are on

directly opposite sides of the piston.

8676

CYLINDER/CYLINDER HEAD 
ASSEMBLY

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Cleaning/Inspecting Cylinder Head

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

any carbon buildup from the combustion chamber

being careful not to nick, scrape, or damage the

combustion chamber or the sealing surface.

2. Inspect the spark plug hole for any damaged

threads. Repair damaged threads using a

“heli-coil” insert.

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RepairPro Service Manual

8

3. Place the cylinder head on the surface plate

covered with #400 grit wet-or-dry sandpaper.

Using light pressure, move the cylinder head in a

figure eight motion. Inspect the sealing surface for

any indication of high spots. A high spot can be

noted by a bright metallic finish. Correct any high

spots before assembly by continuing to move the

cylinder head in a figure eight motion until a

uniform bright metallic finish is attained.

?8)

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Measuring Cylinder Head 
Distortion

1. Remove any carbon buildup in the combustion

chamber.

2. Lay a straightedge across the cylinder head; then

using a feeler gauge, check the distortion factor

between the head and the straightedge.

3. Maximum distortion is 0.05 mm (0.002 in.).

??)

4)

Cleaning/Inspecting Cylinder

1. Wash the cylinder in parts-cleaning solvent.

2. Inspect the cylinder for pitting, scoring, scuffing,

warpage, and corrosion. If marks are found, repair

the surface using a cylinder hone (see Honing

Cylinder in this sub-section).

3. Place the cylinder on the surface plate covered

with #400 grit wet-or-dry sandpaper. Using light

pressure, move the cylinder in a figure eight

motion. Inspect the sealing surface for any

indication of high spots. A high spot can be noted

by a bright metallic finish. Correct any high spots

before assembly by continuing to move the

cylinder in a figure eight motion until a uniform

bright metallic finish is attained.

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9)

Inspecting Cam Chain Guide

1. Inspect cam chain guide for cuts, tears, breaks, or

chips.

2. If the chain guide is damaged, it must be replaced.

Honing Cylinder

1. Using a slide gauge and a dial indicator or a snap

gauge, measure the cylinder bore diameter in three

locations from top to bottom and again from top to

bottom at 90° from the first measurements for a

total of six measurements. The trueness

(out-of-roundness) is the difference between the

highest and lowest reading. Maximum trueness

(out-of-roundness) must be 0.05 mm (0.002 in.).

98)

8)

2. Wash the cylinder in parts-cleaning solvent.

3. Inspect the cylinder for pitting, scoring, scuffing,

and corrosion. If marks are found, repair the

surface using a rigid cylinder hone.

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4. If any measurement exceeds the limit, hone the

cylinder and install an oversized piston or replace

the cylinder.

„

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RepairPro Service Manual

84

'76?

Measuring Camshaft Runout

„

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1. Place the camshaft on a set of V blocks; then

position the dial indicator contact point against the

shaft and zero the indicator.

9?)

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2. Rotate the camshaft and note runout; maximum

tolerance is 0.10 mm (0.004 in.).

Measuring Camshaft Lobe Height

1. Using a calipers, measure each cam lobe height.

'7

2. On the 250/300, the intake lobe height must be a

minimum 33.820 mm (1.331 in.); exhaust lobe

height must be a minimum 33.490 mm (1.318 in.).

On the 375, the intake/exhaust lobe heights must

be 32.830 mm (1.293 in.). On the 400/500, intake

lobe height must be a minimum 33.150 mm (1.305

in.); exhaust lobe height must be a minimum

33.220 mm (1.308 in.).

Inspecting Camshaft Bearing 
Journal

1. Inspect the bearing journal for scoring, seizure

marks, or pitting.

2. If excessive scoring, seizure marks, or pitting is

found, the cylinder head assembly must be

replaced.

Measuring Camshaft to 
Cylinder Head Clearance

1. Remove the adjuster screws and jam nuts.

478)

85

3

775)

2. Place a strip of plasti-gauge in each of the

camshaft lands in the cylinder head.

3. Place the valve cover on the cylinder head and

secure with the valve cover cap screws. Tighten

securely.

„

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4. Remove the cap screws securing the valve cover to

the cylinder; then remove the valve cover and

camshaft.

68)

77)

5. Match the width of the plasti-gauge with the chart

found on the plasti-gauge packaging to determine

camshaft to cylinder head and valve cover

clearance.

45)

6. If clearance is excessive, measure the journals of

the camshaft.

99)

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Inspecting Camshaft Spring/Drive 
Pin (400/500)

1. Inspect the spring and drive pin for damage.

RepairPro Service Manual

86

74)

76)

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2. If damaged, the camshaft must be replaced.

Servicing Left-Side 

Components

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