Yamaha YZ450F 2021 - Removing the Clutch; Checking the Friction Plates; Checking the Clutch Plates; Checking the Clutch Springs

CLUTCH
5-50
EAM30108
REMOVING THE CLUTCH
1. Remove:
• Clutch boss nut “1”
• Lock washer “2”
• Clutch boss “3”
TIP
• Straighten the lock washer tab.
• While holding the clutch boss with the univer-
sal clutch holder “4”, loosen the clutch boss
nut.
EAM30109
CHECKING THE FRICTION PLATES
1. Check:
• Friction plate
Damage/wear  Replace the friction plates
as a set.
2. Measure:
• Friction plate thickness
Out of specification  Replace the friction
plates as a set.
TIP
Measure it at four points on the friction plate.
EAM30110
CHECKING THE CLUTCH PLATES
1. Check:
• Clutch plate
Damage  Replace the clutch plates as a
set.
2. Measure:
• Clutch plate warpage
(with a surface plate and thickness gauge)
Out of specification  Replace the clutch
plates as a set.
EAM30111
CHECKING THE CLUTCH SPRINGS
1. Check:
• Clutch spring
Damage  Replace the clutch springs as a
set.
2. Measure:
• Clutch spring free length
Out of specification  Replace the clutch
springs as a set.
EAM30112
CHECKING THE CLUTCH HOUSING
1. Check:
• Clutch housing dogs “1”
Damage/pitting/wear  Deburr the clutch
housing dogs or replace the clutch housing.
TIP
Pitting on the clutch housing dogs will cause er-
ratic clutch operation.
Universal clutch holder
90890-04086
Universal clutch holder
YM-91042
Friction plate 1 thickness
2.92–3.08 mm (0.115–0.121 in)
Wear limit
2.82 mm (0.111 in)
Friction plate 2 thickness
2.92–3.08 mm (0.115–0.121 in)
Wear limit
2.82 mm (0.111 in)
1
1
1
2
2
3
3
4
4
Thickness gauge
90890-03268
Feeler gauge set
YU-26900-9
Warpage limit
0.10 mm (0.004 in)
Clutch spring free length
48.00 mm (1.89 in)
Clutch spring free length limit
45.60 mm (1.80 in)
1
1
1