FRONT FORK

Removing the front fork legs

Order

Job/Parts to remove

Q’ty

Remarks

 

 

 

Use a maintenance stand to raise the front wheel off the ground.

 

Front wheel

 

Refer to FRONT WHEEL.

 

Front brake caliper

 

Refer to FRONT BRAKE.

 

Headlight

 

Refer to GENERAL CHASSIS.

1

Protector

1

 

2

Upper bracket pinch bolt

2

Loosen.

3

Damper assembly

1

Loosen.

4

Lower bracket pinch bolt

2

Loosen.

5

Front fork leg

1

[“a” = 8 mm (0.3 in)]

Disassembling the front fork leg

Order

Job/Parts to remove

Q’ty

Remarks

1

Adjuster

1

 

2

Fork spring

1

 

3

Damper adjusting rod

1

 

4

Dust seal

1

 

5

Scraper

1

 

6

Stopper ring

1

 

7

Inner tube

1

 

8

Outer tube

1

 

9

Piston metal

1

 

10

Protector guide

1

 

11

Slide metal

1

 

12

Washer

1

 

13

Oil seal

1

 

14

Adjuster knob

1

 

15

Base valve

1

 

16

Damper assembly

1

 

17

Upper spring seat

1

 

REMOVING THE FRONT FORK LEGS

1.Use a maintenance stand to raise the front wheel off the ground.

Securely support the vehicle so that there is no danger of it falling over.

Record the adjusting screw setting position before loosening the adjuster and the base valve.

2.Loosen:

  • Upper bracket pinch bolt

  • Damper assembly

  • Lower bracket pinch bolt

Before loosening the upper and lower bracket pinch bolts, support the front fork leg.

Before removing the front fork leg from the vehicle, loosen the damper assembly “1” with the cap bolt ring wrench “2”.

  • Cap bolt ring wrench

    90890-01501

  • Cap bolt ring wrench

    YM-01501

3.Remove:

  • Front fork leg

DISASSEMBLING THE FRONT FORK LEGS

1.Drain:

  • Fork oil

2.Remove:

  • Adjuster “1”

    (from the inner tube)

  • While compressing the inner tube “2”, set the cap bolt ring wrench “4” between the inner tube and locknut “3”.

  • Hold the locknut and remove the adjuster.

Do not remove the locknut as the damper rod may go into the damper assembly and not be taken out.

  • Cap bolt ring wrench

    90890-01501

  • Cap bolt ring wrench

    YM-01501

3.Remove:

  • Dust seal “1”

  • Stopper ring “2”

    (with a flat-head screwdriver)

Do not scratch the inner tube.

4.Remove:

  • Inner tube “1”

a.Push in slowly “a” the inner tube just before it bottoms out and then pull it back quickly “b”.

b.Repeat this step until the inner tube can be pulled out from the outer tube.

5.Remove:

  • Adjuster knob

  • Base valve “1”

    (from the damper assembly)

  • Before loosening the damping force adjuster, record the setting position.

  • Unless the damping force adjuster is fully loosened, correct damping characteristic cannot be obtained after installation.

  • Hold the damper assembly with the cap bolt ring wrench “2” and use the cap bolt wrench “3” to remove the base valve.

  • Cap bolt wrench

    90890-01911

  • Cap bolt ring wrench

    90890-01501

  • Cap bolt ring wrench

    YM-01501

CHECKING THE FRONT FORK LEGS

1.Check:

  • Inner tube surface

    Scratches → Repair or replace.

    Use #1000 grit wet sandpaper.

    Damaged oil lock piece → Replace.

  • Inner tube bends

    Out of specification → Replace.

    Use the dial gauge.

  • Inner tube bending limit

    0.2 mm (0.01 in)

The bending value is shown by one half of the dial gauge reading.

Do not attempt to straighten a bent inner tube as this may dangerously weaken it.

2.Check:

  • Outer tube

    Scratches/wear/damage → Replace.

3.Measure:

  • Fork spring free length “a”

    Out of specification → Replace.

  • Fork spring free length limit

    492.0 mm (19.37 in)

4.Check:

  • Damper assembly “1”

    Bend/damage → Replace.

  • O-ring “2”

    Wear/damage → Replace.

  • The front fork leg has a built-in damper adjusting rod and a very sophisticated internal construction, which are particularly sensitive to foreign material.

  • When disassembling and assembling the front fork leg, do not allow any foreign material to enter the front fork.

5.Check:

  • Base valve “1”

    Wear/damage → Replace.

    Contamination → Clean.

  • O-ring “2”

    Wear/damage → Replace.

  • Base valve bushing

    Wear/damage → Replace.

  • Fork spring “3”

    Damage/fatigue → Replace the base valve.

  • Bleed screw “4”

    Wear/damage → Replace.

6.Check:

  • Upper spring seat “1”

    (contacting surface “a”)

    Wear/damage → Replace.

7.Check:

  • Adjuster “1”

  • O-ring “2”

    Wear/damage → Replace.

8.Check:

  • Scraper “1”

    Damage → Replace.

ASSEMBLING THE FRONT FORK LEGS

  • Make sure the oil levels in both front fork legs are equal.

  • Uneven oil levels can result in poor handling and a loss of stability.

  • When assembling the front fork leg, be sure to replace the following parts:

    • Inner tube bushing

    • Slide metal

    • Oil seal

    • Copper washer

  • Before assembling the front fork leg, make sure that all of the components are clean.

1.Stretch the damper assembly fully.

2.Fill:

  • Damper assembly

  • Recommended oil

    Yamaha Suspension Oil S1

  • Standard oil amount

    219 cm³ (7.40 US oz, 7.72 Imp.oz)

  • Be sure to use the recommended oil. Other oils may have an adverse effect on front fork performance.

  • When disassembling and assembling the front fork leg, take care not to allow any foreign material to enter the front fork.

3.After filling, pump the damper assembly “1” slowly up and down (about 200 mm (7.9 in) stroke) several times to bleed the damper assembly of air.

Avoid excessive full stroke. A stroke of 200 mm (7.9 in) or more will cause air to enter. In this case, repeat the steps (1) to (3).

4.Measure:

  • Oil level (left and right) “a”

    Out of specification → Regulate.

  • Standard oil level

    143–146 mm (5.63–5.75 in)

    From top of fully stretched damper assembly.

5.Tighten:

  • Locknut “1”

Fully finger tighten the locknut onto the damper assembly.

6.Install:

  • Base valve “1”

    (to the damper assembly “2”)

First bring the damper rod pressure to a maximum. Then install the base valve while releasing the damper rod pressure.

7.Check:

  • Damper assembly

    Not fully stretched → Repeat the steps (1) to (7).

8.Tighten:

  • Base valve “1”

  • Screw (adjuster knob)

  • Base valve

    28 N·m (2.8 kgf·m, 21 lb·ft)

  • Screw (adjuster knob)

    0.6 N·m (0.06 kgf·m, 0.44 lb·ft)

Hold the damper assembly with the cap bolt ring wrench “2” and use the cap bolt wrench “3” to tighten the base valve.

  • Cap bolt wrench

    90890-01911

  • Cap bolt ring wrench

    90890-01501

  • Cap bolt ring wrench

    YM-01501

9.After filling, pump the damper assembly “1” slowly up and down more than 10 times to distribute the fork oil.

10.While protecting the damper assembly “1” with a cloth and compressing fully, allow excessive oil to overflow on the base valve side.

Take care not to damage the damper assembly.

11.Allow the overflowing oil to escape at the hole “a” in the damper assembly.

The overflow measures about 10 cm³ (0.34 US oz, 0.35 Imp.oz).

12.Check:

  • Damper assembly smooth movement

    Tightness/binding/rough spots → Repeat the steps (1) to (12).

13.Install:

  • Dust seal “1”

  • Scraper “2”

  • Stopper ring “3”

  • Oil seal “4”

  • Washer “5”

  • Slide metal “6”

    (to the inner tube “7”)

Make sure that the numbered side of the oil seal faces bottom side.

  • Apply the lithium-soap-based grease on the dust seal lip and oil seal lip.

  • Apply the fork oil on the inner tube.

  • Install the scraper to the inner tube as shown in the illustration.

  • When installing the oil seal, use vinyl seat “a” with fork oil applied to protect the oil seal lip.

14.Install:

  • Piston metal “1”

Install the piston metal onto the slot on inner tube.

15.Install:

  • Outer tube “1”

    (to the inner tube “2”)

16.Install:

  • Slide metal “1”

  • Washer “2”

    (to the outer tube)

Press the slide metal into the outer tube with fork seal driver “3”.

  • Fork seal driver

    90890-01502

  • Fork seal driver (48)

    YM-A0948

17.Install:

  • Oil seal “1”

Using a fork seal driver “2”, press the oil seal in until the stopper ring groove fully appears.

  • Fork seal driver

    90890-01502

  • Fork seal driver (48)

    YM-A0948

18.Install:

  • Stopper ring “1”

Fit the stopper ring correctly in the groove in the outer tube.

19.Install:

  • Scraper “1”

  • Dust seal “2”

Apply lithium-soap-based grease on the inner tube.

20.Check:

  • Inner tube smooth movement

    Tightness/binding/rough spots → Repeat the steps (13) to (20).

21.Measure:

  • Distance “a”

    Out of specification → Turn the locknut to specification.

  • Distance “a”

    16 mm (0.63 in) or more
    Between the damper assembly “1” bottom and locknut “2” bottom.

22.Install:

  • Upper spring seat “1”

  • Fork spring “2”

    (to the damper assembly “3”)

Install the upper spring seat with its larger dia. end “a” facing the fork spring.

23.Install:

  • Damper assembly “1”

    (to the inner tube “2”)

Allow the damper assembly to slide slowly down the inner tube until it contacts the bottom of the inner tube. Be careful not to damage the inner tube.

24.Loosen:

  • Rebound damping force adjuster “1”

  • Before loosening the damping force adjuster, record the setting position.

  • Unless the damping force adjuster is fully loosened, correct damping characteristic cannot be obtained after installation.

25.Install:

  • Damper adjusting rod “1”

  • Copper washer “2”

  • Adjuster “3”

    (to the damper assembly “4”)

  • While compressing the inner tube “5”, set the cap bolt ring wrench “7” between the inner tube and locknut “6”.

  • Fully finger tighten the adjuster onto the damper assembly.

  • Cap bolt ring wrench

    90890-01501

  • Cap bolt ring wrench

    YM-01501

26.Measure:

  • Gap “a” between the adjuster “1” and the locknut “2”

    Out of specification → Retighten and readjust the locknut.

  • Gap “a” between the adjuster and the locknut

    0.5–1.0 mm (0.02–0.04 in)

If it is installed with a gap out of specification, correct damping force cannot be obtained.

27.Tighten:

  • Adjuster (damper assembly) “1”

  • Adjuster (damper assembly)

    29 N·m (2.9 kgf·m, 21 lb·ft)

Hold the locknut “2” and tighten the adjuster.

28.Install:

  • Adjuster “1”

    (to the inner tube)

  • Adjuster

    55 N·m (5.5 kgf·m, 41 lb·ft)

    LOCTITE®

29.Fill:

  • Front fork leg

  • Recommended oil

    Yamaha Suspension Oil S1

  • Standard oil amount

    285 cm³ (9.64 US oz, 10.05 Imp.oz)

  • Extent of adjustment

    260–370 cm³ (8.79–12.51 US oz, 9.17–13.05 Imp.oz)

  • Be sure to use the recommended oil. Other oils may have an adverse effect on front fork performance.

  • When disassembling and assembling the front fork leg, do not allow any foreign material to enter the front fork.

30.Install:

  • Damper assembly “1”

    (to the outer tube)

Temporarily tighten the damper assembly.

31.Install:

  • Protector guide “1”

INSTALLING THE FRONT FORK LEGS

1.Install:

  • Front fork “1”

  • Temporarily tighten the lower bracket pinch bolts.

  • Do not tighten the upper bracket pinch bolts yet.

2.Tighten:

  • Damper assembly “1”

  • Damper assembly

    30 N·m (3.0 kgf·m, 22 lb·ft)

Use the cap bolt ring wrench “2” to tighten the damper assembly.

  • Cap bolt ring wrench

    90890-01501

  • Cap bolt ring wrench

    YM-01501

3.Adjust:

  • Front fork top end “a”

  • Front fork top end (standard) “a”

    8 mm (0.3 in)

4.Tighten:

  • Upper bracket pinch bolt “1”

  • Upper bracket pinch bolt

    21 N·m (2.1 kgf·m, 15 lb·ft)

  • Lower bracket pinch bolt “2”

  • Lower bracket pinch bolt

    21 N·m (2.1 kgf·m, 15 lb·ft)

Tighten the lower bracket to specified torque. If torqued too much, it may cause the front fork to malfunction.

5.Install:

  • Speed sensor lead “1”

  • Front brake hose “2”

  • Plate “3”

    (to the left front fork protector)

  • Plate bolt

    3.8 N·m (0.38 kgf·m, 2.8 lb·ft)

6.Install:

  • Protector “1”

  • Front fork protector bolt “2”

  • Front fork protector bolt

    5 N·m (0.5 kgf·m, 3.7 lb·ft)

7.Adjust:

  • Rebound damping force

Turn in the damping adjuster “1” finger-tight and then turn out to the originally set position.

8.Adjust:

  • Compression damping force

Turn in the damping adjuster “1” finger-tight and then turn out to the originally set position.