Snowmobile Arctic Cat 2-Stroke (2007 year). Manual - part 28

2-98

726-306A

3. Apply oil to the connecting-rod small end bear-

ings; then install the small-end bearings. Install a

washer on each side of the connecting rod.

„NOTE: The shoulder side of the washer must
seat to the needle bearing.

CM172A

„NOTE: Prior to installing the pistons, make sure
to install the MAG-side piston pin circlips first.

4. Place each piston over the connecting rod so the

indicator dot on each piston will point toward the

intake/exhaust ports; then secure with an oiled pis-

ton pin.

„NOTE: The indicator dot (A) is found on the pis-
ton dome.

CM194A

5. Install the new circlips so the open end is directed

either up or down.

CM195B

6. Rotate each piston ring until the ring ends are

properly positioned on either side of the ring

keeper; then apply oil to the piston assemblies and

cylinder bores. Remove the rubber hoses from the

connecting rods.

7. In turn on each cylinder, place a piston holder (or

suitable substitute) beneath the piston skirt and

square the piston in respect to the crankcase; then

using a ring compressor or the fingers, compress

the rings and slide the cylinder over the piston.

Remove the piston holder and seat the cylinder

firmly onto the crankcase.

! CAUTION

Incorrect installation of the piston rings will result in
engine damage.

! CAUTION

Make sure the circlips are firmly seated and the open
end is directed either up or down before continuing
with assembly.

! CAUTION

The cylinders should slide on easily. DO NOT force
the pistons into the cylinders.

2-99

2

CM192

8. Secure each cylinder by installing the four nuts

and four cap screws. DO NOT TIGHTEN AT

THIS TIME.

„NOTE: Never reuse cylinder cap screws. Always
replace with new cap screws.

„NOTE: The cylinders will be tightened after the
exhaust manifold is installed to assure proper cyl-
inder to exhaust manifold alignment.

9. Apply a thin coat of high-temperature silicone

sealant to each exhaust port; then install the

exhaust gaskets.

CM196

10. Apply a thin coat of high-temperature silicone

sealant to the mating surfaces of the exhaust mani-

fold; then install the exhaust manifold and secure

with eight nuts. Tighten the nuts in a crisscross

pattern to specifications.

0742-292

11. Secure the cylinders (from step 8) by tightening

the cylinder base nuts and cap screws to specifica-

tions in three steps using the appropriate pattern

shown.

0738-206

0738-220

12. Install the hose clamp onto the cylinder head cool-

ant hose with the clamp screw directed outward

(toward the PTO-side of the engine).

CM199A

13. Install the coolant hose and secure the hose onto

the cylinder head; then install the coolant bypass

hose onto the head.

„NOTE: On the 1000 cc, install the coolant bypass
hoses onto the cylinders.

„NOTE: After the coolant hose has been secured
to the cylinder head, secure the cylinder head up
and out of the way of the cylinder to allow the cyl-
inder O-rings to be installed.

800 cc

1000 cc

2-100

CM191

14. Install the two cylinder O-rings on the top of each

cylinder making sure they are correctly positioned

in the grooves.

FC077

15. Place new O-rings onto each of the head cap

screws. Place four of these cap screws (from oppo-

site end of each other) into the cylinder head.

Thread the spark plugs in part way; then while

holding the head above the cylinder, carefully start

all four cap screws while observing the cylinder

O-rings to make sure they remain in position.

Slowly place the head into position on top of the

O-rings. 

CM175

„NOTE: On the 800 cc prior to starting the remain-
ing cap screws, the spark plugs must be removed.

16. Start the remaining cap screws being very careful

not to move the cylinder head. ONLY FINGER-

TIGHTEN AT THIS TIME; then tighten the cap

screws in two steps to specifications using the

appropriate pattern shown.

0742-200

0742-199

17. On the 800 cc, install the spark plugs and on both

models, tighten the spark plugs to specifications;

then install the spark plug wires.

„NOTE: On the 800 cc, connect the knock sensor
plug-in.

18. With the raised edge (A) of the bottom of the valve

aligned with the channel (B) of the cylinder, install

the APV’s onto the cylinder and secure with the

cap screws. Tighten to specifications.

CM147A

19. Install the side-plate brace; then secure with exist-

ing hardware.

800 cc

1000 cc

2-101

2

„NOTE: It is advisable to install the two front lower
cap screws first to attain proper alignment for the
remaining cap screws.

CM133B

20. With the throttle body coolant hose secured to the

water pump, fill the cooling system with recom-

mended coolant (see Liquid Cooling System in

Section 3).

CM201A

21. Install the expansion chamber and resonator using

existing hardware. 

22. Install and secure the left-side and right-side

access panels and the hood.

23. Start the engine and warm up to operating temper-

ature; then verify that all components are function-

ing properly and that coolant is circulating through

the cooling system properly.

24. Allow the engine to cool; then check the coolant

level and add coolant as necessary.

25. Install the skid plate.

Cleaning and Inspecting 

Engine

„NOTE: Whenever a part is worn excessively,
cracked, or damaged in any way, replacement is
necessary.

CYLINDER HEAD

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

warpage must not exceed 0.05 mm (0.002 in.).

„NOTE: If the warpage exceeds specification,
resurface the cylinder head using procedures
identified in step 4.

FS270

! CAUTION

Never run the engine with the hood harness discon-
nected or damage to the electrical system will result.

! CAUTION

After running the engine to the proper operating tem-
perature, shut the engine off; then open the hood
and remove access panels and inspect for any signs
of coolant, gasoline, or oil leakage.

! CAUTION

If the engine had a major overhaul or if any major
component was replaced, proper engine break-in
procedures must be followed. If the proper engine
break-in procedures are not followed, severe engine
damage may result.