| Do you have a reasonable idea of the dimensions.
The clips have various names R clip, clevis pin clip,
If Ducati related sources draw a blank it might be worth a trip to your local farm machinery suppliers, they use pretty large clevis pin clips on..........er tractors and farm machinery.
Some motorsport suppliers have them in stock as well as similar clips are used as wheel nut retainers etc.
It's a reasonably generic part unless of course Ducati had some made to a particular spec/dimension.
Good luck in the search.
Ray | 
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