Snowmobile Arctic Cat 2-Stroke (2007 year). Manual - part 11

2-30

FC046

4. Position the indicator contact point against the

crankshaft at location point E (center). Zero the

indicator and rotate the crankshaft slowly. Note

the amount of crankshaft runout (total indicator

reading).

5. If runout exceeds specifications at any of the

checkpoints, the crankshaft must be either

straightened or replaced.

Assembling Engine

„NOTE: The use of new gaskets and seals is rec-
ommended when assembling the engine.

„NOTE: When the use of a lubricant is indicated,
use Arctic Cat 50:1 Injection Oil.

1. Install the C-ring and the five bearing retaining

pins into the lower crankcase half.

2. Lubricate the inner lips of the crankshaft oil seals

with grease; then slide the seals onto the crank-

shaft making sure the spring side of each seal faces

the center of the crankshaft.

AC087

3. Apply oil to the crankshaft bearings; then install

the dowel pins, C-ring, and crankshaft into the

lower crankcase half. Be sure the alignment hole

in each bearing is positioned over its respective

bearing retaining pin in the crankcase; then seat

the crankshaft.

MS986A

„NOTE: Make sure the crankshaft center seal is
properly positioned in the groove of the lower
crankcase half.

„NOTE: To check the bearing for proper position,
place the point of a sharp tool into the dimple
found in the bearing race. Strike the tool with the
palm of the hand in either direction. If the bearing
moves, it isn't positioned correctly and must be
rotated until it drops onto the dowel pin.

4. Apply a thin coat of Three Bond Sealant (p/n

0636-070) to the crankcase sealing surfaces.

5. Assemble the crankcase halves making sure the

crankcase dowel pins are properly positioned and

the end seal tab will not block the oil transfer port

in the upper crankcase half.

AB092A

6. Install the crankcase cap screws making sure the

cap screws are in the corresponding-sized holes.

Tighten in three steps the 8 mm cap screws to

specifications and the 6 mm cap screws to specifi-

cations using the pattern shown.

! CAUTION

If the bearings are not properly seated during
assembly, the crankcase halves will not seal tightly
and engine damage will result.

2-31

2

0726-412

„NOTE: Secure the connecting rods with rubber
bands on the cylinder studs.

B160

7. Install the piston rings on each piston so the letter

on the top (inclined surface) of each ring faces the

dome of the piston.

726-306A

AC088

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

ings; then install the small-end bearings into the

connecting rods.

„NOTE: Apply oil to the piston pin before installing.

9. Place each piston over the connecting rod so the

arrow on the piston dome points toward the

exhaust port; then secure with a piston pin.

„NOTE: The arrow is found either up inside the
piston or on the dome top.

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

either down or up.

B324D

11. Install the cylinder base gaskets onto the crankcase

making sure each gasket aligns with crankcase

transfer passages.

12. Rotate each piston ring until the ring ends are

properly positioned on each side of the ring

keeper; then apply oil to the piston assemblies and

cylinder bores. Remove the rubber bands from the

connecting rods.

726-306B

! CAUTION

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

! CAUTION

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

2-32

„NOTE: Apply a generous amount of oil to the sur-
faces of the pistons, rings, and cylinder bores.

„NOTE: Inspect the cylinder-base gasket to
ensure proper positioning.

13. For each piston, 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 pis-

ton holder and seat the cylinder firmly onto the

crankcase.

A828A

14. Place each cylinder head with dowel pins and gas-

ket into position and install the eight nuts. DO

NOT TIGHTEN AT THIS TIME.

15. Temporarily install the exhaust manifold and

secure with four nuts and lock washers to square

the cylinders. Tighten the manifold nuts to specifi-

cations.

16. With the exhaust manifold in place, tighten the

cylinder head nuts (from step 14) in three steps to

specifications using the pattern shown.

0725-318

17. In order, install the gear, shim, gasket, retainer,

gasket, and oil-injection pump. Secure with two

screws, lock washers, and washers. Tighten to

specifications.

AB078

„NOTE: If removed, secure the ignition coil to the
fan case.

18. Align the reference marks made during disassem-

bly; then secure the stator plate with two Allen-

head cap screws (coated with red Loctite #271),

lock washers, and washers.

„NOTE: Before installing the flywheel, wipe the
crankshaft and flywheel taper clean using a clean
cloth.

19. Install the key in the crankshaft and slide the fly-

wheel onto the crankshaft making sure the key-

ways match.

20. Place the fan case into position and secure with

four nuts. Tighten the nuts to specifications.

A814

21. Apply a thin coat of High-Temp Sealant (p/n

0636-069) to both sides of the intake gaskets; then

in order, install a gasket (one on each port),

shroud, gasket (one on each port), insulator (one

on each port), gasket (one on each port), and

intake manifold. 

22. Secure with nuts (threads coated with red Loctite

#271). Tighten nuts in three steps to specifications.

! CAUTION

Be sure the gear is properly aligned with the slot of
the oil-injection pump shaft. The injection pump will
be damaged if these two components are not aligned.

2-33

2

23. Place the intake flange into position and secure

with nuts (threads coated with red Loctite #271),

lock washers, and washers. Tighten to specifica-

tions.

24. Remove the exhaust manifold.

25. Install spark plugs and tighten to specifications.

26. Attach the oil-injection hoses to their fittings.

Secure with clamps; then test the engine for air

leaks (see Section 3).

27. Temporarily secure the starter pulley on the fly-

wheel with three cap screws. Install the flywheel

washer, lock washer, and nut. Apply red Loctite

#271 to the crankshaft threads before installing the

flywheel nut. Using a spanner wrench to secure

the crankshaft, tighten the flywheel nut to specifi-

cations.

MD2499

28. Remove the starter pulley. Position the fan belt

drive pulley into the belt. Align the starter pulley

holes with those in the belt pulley. Start one of the

cap screws into the flywheel; then rotate the belt

pulley and starter pulley in a counterclockwise

direction.

29. When the pulley pivots on the cap screw, rock the

pulleys backward or forward until the remaining

cap screw holes align. Install the remaining two

cap screws and tighten evenly to specifications.

„NOTE: Apply red Loctite #271 to the threads of
the cap screws before installing.

MD2500

30. Place an exhaust manifold gasket on each exhaust

port making sure the metal side of the gasket faces

the cylinder. Slide the exhaust-side cooling shroud

onto the exhaust port studs; then place the upper

cooling shroud into position and secure the

shrouds with 14 cap screws noting the location of

the longer cap screws from disassembling. Tighten

to specifications. Connect the spark-plug caps.

31. Apply a thin coat of High-Temp Sealant (p/n

0636-069) to the exhaust-manifold gasket; then

place a gasket on each exhaust port making sure

the metal side of each gasket faces away from the

cylinder. Install the exhaust manifold, lock wash-

ers, and nuts and tighten to specifications.

Installing Engine

1. Place each engine mounting bracket onto the

engine. Secure with cap screws (coated with blue

Loctite #243), washers, and lock washers. Tighten

to specifications.

2. Place the engine assembly into position in the

engine compartment. Secure the engine to the

front end with the cap screws, washers, and lock

nuts. Tighten to specifications.

370-ENG07A

3. Connect the oil-supply hose to the oil-injection

pump; then bleed the system (see Section 4).

„NOTE: If equipped with electric start, place the
starter motor bracket on the crankcase and install
the front two and lower rear cap screws, lock wash-
ers, and washers. Place the starter motor into posi-
tion and secure with two washers and lock nuts.

4. Connect the oil-injection cable to the oil-injection

pump control arm and secure the cable mounting

pin with a nylon washer and E-clip.

5. Place the carburetor(s) into position making sure

the boot(s) are properly positioned and secure with

the flange clamp(s).