If they are badly worn or if there are groove cuts where the tangs hit, replace the housing. Also, replace the friction plates if their tangs are damaged.

Clutch Spring Free Length Measurement
Clutch Housing Spline InspectionSpark Plug Condition Inspection
Remove the spark plugs (see Spark Plug Replacement in
the Periodic Maintenance chapter).
Visually inspect the spark plugs.
If the spark plug center electrode [A] and/or side electrode
[B] are corroded or damaged, or if the insulator [C]
is cracked, replace the plug.
If the spark plug is ...
Gear Position Switch Removal
Remove:
Oil Pump (see Oil pump Removal in the Engine Lubrication
System chapter)
Engine Sprocket (see Engine Sprocket Removal in the
Final Drive chapter)
Fuel Tank (see Fuel Tank Removal in the Fuel System
(DFI) chapter)
Disconnect the connector [A].
Remove:
Screws [A]
...
Exhaust Butterfly Valve Cable Installation
Confirm whether pulley [A] is an angle shown in the figure.
41.7° ±7° [B]
This position is original position of the pulley.
NOTE
Correct the position electrically after confirming the use
is discontinued and there is no damage when differing
from the angle of shown in the figure.
...