No...it isn't the same old what is better clip or rivit question...

Conversion from OEM 525 to an aftermarket 520 setup on an R6. Unknown chain brand but it is definitely a 520 o-ring. Stamping on the connector link is LM520 and it is/was a clip type link. Standard o-ring links bind and will not free up when installed...pin size is too big. Does anyone know of another 520 link that uses pin sizes other than the "standard" o-ring replacement. I'm guessing that it is less than .002 difference in size but definitely needs to be smaller. Brand and vendor source would be very helpful. Thanks for any info...

Master links are very often specific to the make and model of chain. There is no "universal" 520 or 530 o-ring or x-ring master link. That's one reason why random posts for master links aren't very useful. You'll need to know the make and model of your chain to ensure you get the correct one...or measure the old one. Even the original equipment DID chain on the XX does not use the same master link as the aftermarket DID ZVM...they have different pin diameters.

I just went through a similar process, go to your local part's house & have them match up a master link, Have you tried that already ?
Do you know what mm size pin diameter you need ?