Have you tried any motorcycle shops or Ebay?
Personally, I like DID for chains.
Sprockets I'm not too fussy about and have used AFAM, Renthal, JT among others, all in 520 aluminium and never had any problems.
If you're happy with the chain you have now then it should have stamped on the side plates what brand and model of chain it is.
You have two sprockets and I suggest you check both and see what's stamped on them regarding number of teeth, brand and whether they're 520 or 530.
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