I assume you mean rectifier/regulator.
It might be like mine in that the stator has just had to be replaced as it was not charging while riding, and battery would go flat.
There is a test procedure on this forum, or internet(google) or the repair manual will explain it.
I was a bit over whelmed by it all and just let the shop handle it, but if you are electrically inclined, go for it, and save a ton .
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