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Snowmobile Arctic Cat (2004 year). Instruction - part 34

2-123

CYLINDER HEAD VOLUME TESTS

CYLINDER HEAD VOLUME
(Squish-Gap Method)

To check the squish gap, a micrometer and a heavy
piece of solder will be needed.

1. Remove the spark plugs from the engine.

2. Insert the solder piece down through the spark

plug hole and push it up against the inner cylinder
bore towards the MAG-side of the engine.

3. Pull the recoil rope and crank the engine over

several times while the solder is being held firmly
in place.

4. Remove the solder from the cylinder. Using the

micrometer, measure the very end of the squeezed
solder piece. Record the reading.

NOTE: If the solder hasn’t been squeezed by the

piston, a larger piece of solder must be used.
Repeat procedure.

5. Using the opposite end of the solder piece, insert it

down through the spark plug hole towards the
PTO-side of the engine. Push on the solder until it
contacts the inner cylinder bore.

6. Pull the recoil rope and crank the engine over

several times. Remove the solder from the
cylinder and measure the squeezed end with a
micrometer. Record reading and refer to the chart.

NOTE: Measure from PTO to MAG-side of the

piston to accurately measure the squish gap.
Never measure across piston, exhaust to carbure-
tor side, as the piston will rock and the reading
won’t be accurate.

Readings may vary from side to side. Make sure the
smaller reading is within the specifications listed.

CYLINDER HEAD VOLUME
(Cylinder Head
Installed Method)

To check the cc volume, a measuring tool called a
buret will be needed. It is capable of measuring a liq-
uid in cc volumes.

1. Fill buret with 10W engine oil.

2. Remove the spark plugs from the cylinders.

3. Run piston up to TDC (Top Dead Center).

4. Insert buret into spark plug hole and open buret

valve. Run oil into the spark plug hole until it
reaches the top of the spark plug hole. Turn off the
buret valve.

5. Check the buret scale to see how much oil has

been used to fill the combustion chamber. From
the total amount, subtract 2.20 cc or 2.44 cc.
Compare the findings with the chart.

NOTE: The above procedure will work fine on a

new engine. Engines with many hours of use, may
require a small change in the procedure. In step 3,
remove the cylinder head. Wipe a small amount of
heavy grease around the outer diameter of the pis-
ton to seal space between the piston and cylinder
bore. Replace head and tighten to specification;
then continue with steps 4 and 5.

CYLINDER HEAD VOLUME
(Flat Plate Method)

The third method of checking for proper combustion
chamber volume will require a 1/8 in. or 3/16 in. thick
piece of plexiglass, some heavy grease, and a buret.

The plexiglass piece must be flat and also large enough
to cover the entire gasket surface of the cylinder head.
Using a 3/16 in. drill bit, drill two holes through the
plexiglass piece. Locate the holes one inch apart inside
the combustion chamber area (towards center of
piece).

1. Remove the cylinder head from the engine. Clean

all carbon from the combustion chamber area.

2. Position the cylinder head squarely in a vise with

its gasket surface up. Leave a BR9ES spark plug
in place and grip the metal portion of the spark
plug for holding the cylinder head.

3. Apply a light coat of grease to the gasket surface

of the head. Squeeze the piece of plexiglass firmly
down onto the gasket surface. The grease will act
as a sealant between the two pieces.

4. Using a buret filled with light oil, fill the

combustion chamber through either of the two
holes drilled in the plexiglass. Continue to fill the
combustion chamber until the fluid appears at the
bottom of the second hole. Stop filling procedure
and take a reading off the buret as to how much
fluid was used. The specification found in the
chart includes the spark plug volume, so there
won’t be any need to subtract from the reading.

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CRANKSHAFT REPAIR

For those who have crankshaft work sent out to another shop, it is advisable to provide them with this information.

To use the specifications, first refer to the drawing; then find the letter which indicates the specification and refer to
the chart below the illustration. Be sure to note the proper engine column. Specifications are called out in both mil-
limeters and inches.

NOTE: We have given the proper location for checking crankshaft runout as the very edge of the straight

portion of the shaft where the oil seal makes contact. From the drawings on page 23 of this section, note
that Arctic Cat has called out three check points: at either end, out on the taper as shown, and also on the
center bearing race. The crankshaft is still supported on the outer bearings using V blocks. The maximum
runout shouldn’t exceed 0.05 mm (0.002 in.).

3-1

SECTION 3 — ENGINE-RELATED ITEMS

TABLE OF

CONTENTS

3-2

Axial Fan/Belt

(370/440 cc)

REMOVING FAN

1. Remove the four cap screws securing the recoil

starter to the fan case.

2. Remove the three cap screws securing the recoil

starter pulley and fan drive pulley to the flywheel;
then remove the recoil starter pulley and fan drive
pulley.

3. Remove the cap screws and flange nuts securing

the fan case assembly to the engine; then remove
the fan case from the engine compartment.

DISASSEMBLING

1. Remove the fan cover; then remove the belt.

2. Using the Fan Spanner Wrench (p/n 0644-139),

remove the nut, lock washer, and washer securing
pulley halves.

AB102

3. Slide the outer pulley half, shim(s), fan belt, and

inner pulley half off the shaft and account for the
key and the fan belt.

A908

4. Remove the fan with shaft.

5. Drive the bearings from the fan case and account

for the spacer between the bearings.

A910

NOTE: A circlip is positioned between the bear-

ings. The bearings must be driven from the center
to the outside of the fan case.

6. Remove the circlip from the fan case.

A911

CLEANING AND INSPECTING

NOTE: Whenever a part is worn excessively,

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

1. Clean all axial fan components.

2. Inspect the fan case and shaft threaded areas for

damage or stripped threads; then check the shaft
keyway and key for excessive wear.

3. Inspect the fan for broken, bent, or damaged

vanes.

4. Inspect the bearings for smooth rotation.

5. Inspect the pulley halves for cracks, gouges, or

other damage.

6. Inspect the fan belt for cracks, tears, or fraying.

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