If it's got a 520 conversion, which I read means just a 520 sprocket on the rim, buy a 530 sprocket and put it on the rim.
You don't want to mix and match, (ie, 520 front sprocket, 525 chain, 530 rear or any combination therein), You want a single number on both sprockets and the chain, but you can use 520 chain/sprockets on a Busa. I'm just led to believe you cannot do so for very long.
Edit: To the best of my knowledge, which could be wrong, the sprocket carrier has no effect on what type of sprocket you can run, as long as the bolts are in the right places.
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