I replaced the stock chain with another of the same length. My point was that a new 108-link chain fits the stock front and a 42t rear sprocket.
My model year is in my profile but is irrelevant because all ZX-6Rs have the same stock gearing and chain length.
The standard aluminum sprocket is not hard anodized. I replaced it at a couple of hundred miles to fit a 520-size counterpart. Put another way, I would be worried about hastened wear on the sprocket, not the chain.
If you are unhappy with the sprocket, it will make a great (and quite light) paper weight. It is not only very reasonably priced, it is free.
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