Hi Tone,
If yours is missing, I think you'll have to do with what you can find. Plunger clutch parts, bar centre and plates, are hard to find.
If you got one, but find the outer basket to wobbly on it, it's possible to skim the back of the clutch centre where it sits against the thrust washer. That's what I did, and it worked out fine.
You may need to revise the chain alignment though.