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Snowmobile Yamaha FX10X, FX10RTX, FX10RTRX, FX10RTRAX, FX10MTX, FX10MTRX, FX10MTRAX. Manual - part 7

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COMPRESSION PRESSURE MEASUREMENT

COMPRESSION PRESSURE
MEASUREMENT

NOTE:

Insufficient compression pressure will result in a
loss of performance.

1. Measure:

• Valve clearance

Out of specification

→ Adjust.

Refer to “VALVE CLEARANCE ADJUST-
MENT”.

2. Start the engine, warm it up for several minutes,

and then turn it off.

3. Remove:

• Fuel tank

Refer to “SEAT AND FUEL TANK” in CHAP-
TER 5.

4. Remove:

• Spark plug

CAUTION:

Before removing the spark plugs, use com-
pressed air to blow away any dirt accumulated
in the spark plug wells to prevent it from falling
into the cylinders.

5. Install:

• Compression gauge 1

Compression gauge:

90890-03081

Engine compression tester:

YU-33223

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COMPRESSION PRESSURE MEASUREMENT

6. Measure:

• Compression pressure

Above the maximum pressure

→ Inspect the

cylinder head, valve surfaces, and piston
crown for carbon deposits.
Below the minimum pressure

→ Squirt a few

drops of oil into the affected cylinder and
measure again.
Refer to the following table.

Measurement steps:

• Set the engine stop switch to “RUN” and turn

the main switch to “START”.

• With the throttle wide open, crank the engine

until the reading on the compression gauge sta-
bilizes.

WARNING

To prevent sparking, disconnect all ignition coil
couplers before cranking the engine.

NOTE:

The difference in compression pressure between
cylinders should not exceed 100 kPa (1 kg/cm

14.2 psi).

7. Install:

• Spark plug

Compression pressure

(with oil applied into cylinder)

Reading

Diagnosis

Higher than
without oil

Piston ring(-s) wear or
damage

→ Repair.

Same as
without oil

Piston, valves, cylinder
head gasket or piston
possibly defective

→

Repair.
Compression pressure (at
sea level)

Compression pressure (at sea level):

Standard:

1,500 kPa (15.0 kg/cm

, 213.3 psi)

at 400 r/min

Minimum:

1,400 kPa (14.0 kg/cm

, 199.1 psi)

at 400 r/min

Maximum:

1,600 kPa (16.0 kg/cm

, 227.5 psi)

at 400 r/min

Spark plug:

13 Nm (1.3 m · kg, 9.4 ft · lb)

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ENGINE OIL LEVEL INSPECTION

1. Inspect:

• Engine oil level

CAUTION:

Do not run the engine with too much or not
enough oil in the oil tank. Oil could flow into the
air filter and the engine could be damaged.

Inspection steps:

• Place the snowmobile on a level surface and

apply the parking brake.

• Start the engine, warm it up for 10 ~ 15 minutes,

and then turn off.

• Remove the right side cover.

Refer to “COVERS” in CHAPTER 3.

• Disconnect the oil level switch coupler 1.

CAUTION:

Disconnect the oil level switch coupler before
removing the oil level gauge. Otherwise the
lead can twist and become severed.

• Remove the oil level gauge 2, wipe it clean,

insert it back into the filler hole (without screw-
ing it in), and then remove it again to check the
oil level.

• The engine oil level should be between the

maximum level mark “H”

a and minimum level

mark “L”

Below the minimum level mark

→ Add the rec-

ommended engine oil to the proper level.

CAUTION:

• When adding the engine oil, be careful not to

fill above the maximum level mark “H” and
minimum level mark “L” on the oil level
gauge.

• Do not allow foreign materials to enter the oil

tank.

È USA/Canada
É Europe

Recommended engine oil type:

For USA/Canada

YAMALUBE 4-S (0W-30) or
SAE 0W-30

For Europe

SAE 0W-30

Recommended engine oil grade:

API service SG type or higher,
JASO standard MA

-40˚

-20˚

-29˚

0˚

-18˚

20˚

-7˚

40˚

4˚

60˚F

16˚C

YAMALUBE 4-S (0W-30) or SAE 0W-30

-40˚

-29˚

-18˚

-7˚

4˚

16˚C

SAE 0W-30

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ENGINE OIL LEVEL INSPECTION/

ENGINE OIL REPLACEMENT

NOTE:

Before checking the engine oil level, wait a few
minutes until the oil has settled.

• Start the engine, warm it up for several minutes,

and then turn it off.

• Check the engine oil level again.

NOTE:

Before checking the engine oil level, wait a few
minutes until the oil has settled.

CAUTION:

• Use only 4-stroke engine oil.
• Engine oil also lubricates the starter clutch. In

order to prevent clutch slippage, do not mix
any chemical additives with the oil or use oils
of a higher grade than “CD”. In addition, do
not use oils labeled “ENERGY CONSERVING
II” or higher.

ENGINE OIL REPLACEMENT

1. Place the snowmobile on a level surface and

apply the parking brake.

2. Start the engine, warm up for several minutes,

and then turn it off.

3. Remove:

• Lower cover (left and right)

Refer to “COVERS” in CHAPTER 3.

4. Place containers under the engine oil pan and

oil tank.

5. Remove:

• Bottom panel 1

6. Disconnect:

• Oil level switch coupler

Refer to “ENGINE OIL LEVEL INSPECTION”.

7. Remove:

• Oil level gauge

Refer to “ENGINE OIL LEVEL INSPECTION”.

8. Remove:

• Cylinder head oil filler cap 1

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