Cush drive rubbers with a hex imprint on them would definitely indicate them being from an MC21, however the MC18 and MC21 use the same part number for the rubbers.

There is usually a small gap between the sprocket carrier face and the wheel on a standard setup, but I can't tell you if/what it should be on an R5K with an MC21 wheel. You will need to fit it all up, and check the sprocket alignment.

I would be surprised if there was anything untoward.
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Andy.
NSR-WORLD.COM

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