Snowmobile Yamaha FX10X, FX10RTX, FX10RTRX, FX10RTRAX, FX10MTX, FX10MTRX, FX10MTRAX. Instruction - part 80

8-14

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ELEC

ELECTRICAL STARTING SYSTEM

STARTER MOTOR

Order

Job name/Part name

Q’ty

Remarks

Starter motor removal

Remove the parts in the order listed below.

Engine assembly

Refer to “ENGINE ASSEMBLY” in CHAPTER 
5.

1

Starter motor lead

1

2

Starter motor assembly

1

For installation, reverse the removal proce-
dure.

Starter motor disassembly

Remove the parts in the order listed below.

1 O-ring

1

2 Front 

bracket

1

3 Gasket

2

4 Bearing

1

5 Oil 

seal

1

6 Rear 

bracket

1

7 Brush

2

8 Brush 

spring

4

8-15

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ELEC

ELECTRICAL STARTING SYSTEM

s

Order

Job name/Part name

Q’ty

Remarks

9 Brush 

holder

1

0 Bearing

1

A Armature 

assembly

1

B 

Starter motor yoke

1

For assembly, reverse the disassembly pro-
cedure.

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ELEC

ELECTRICAL STARTING SYSTEM

Inspection

1. Inspect:

• Commutator (outer surface)

Dirty 

→ Clean with #600 grit sandpaper 1.

Hold the armature in a vise 2 and copper or
aluminium plate 3.

CAUTION:

Lightly grip the armature with a vise.

2. Measure:

• Commutator diameter 

a 

Measure the diameter 

a of the commutator at

points where the brush comes in contact.
Out of specification 

→ Replace the starter

motor.

Commutator diameter wear limit:

27.0 mm (1.06 in)

3. Measure:

• Mica undercut (insulation depth) 

a 

(between commutator segments)
Out of specification 

→ Scrape mica 1 to

proper limits.
Use a hacksaw blade 2 that is ground to fit.

Mica undercut:

1.0 mm (0.04 in)

4. Measure:

• Armature coil resistance 

(insulation/continuity)
Out of specification 

→ Replace the starter

motor.

Inspecting steps:

• Connect the pocket tester for the continuity

check 1 and the insulation check 2.

• Measure the armature coil resistances.

• If the resistance is incorrect, replace the starter

motor.

Armature coil resistance:

Continuity check:

0.0081 ~ 0.0099 

Ω at 20 °C (68 °F) 

Insulation check:

Above 1 M

Ω at 20 °C (68 °F)

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ELEC

ELECTRICAL STARTING SYSTEM

5. Measure:

• Brush length 

a 

Out of specification 

→ Replace the brushes

as a set.

6. Measure:

• Brush spring pressure

Fatigue/out of specification 

→ Replace the

brush spring as a set.

7. Check:

• Bearings
• Oil seal

Damage/wear 

→ Replace the starter motor.

Brush length wear limit:

4.4 mm (0.17 in)

Brush spring pressure:

7.36 ~ 11.04 N 
(750 ~ 1,126 g, 26.49 ~ 39.74 oz)

Assembly

1. Install:

• Gaskets
• Starter motor yoke 1 

(to the rear bracket 2)

NOTE:

Align the projection 

a on the rear bracket with the

slot 

b on the starter motor yoke.

1

a

b

2

New