I'm needing an exhaust gasket donut, suggestion help needed.

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I attached pictures of the problem. I was wanting to know if this is my old gasket, a metal donut, I guess but has been cruched to form a seal maybe. I'm needing to know is this a guide or seat for the missing gasket that I'd guess fell out when I lost a bolt or is it a worn out gasket?

Thanks

As with most motorcycle exhaust to head connections it is a crush washer..or as you say donut. It is a one time use. If it is released..loosened..it needs to be replaced. It crushes to fit when tightened. Once the bolts are loosened its done..