Cycle oil leak

Lot of knowledgeable people here, looking for advice. My Yamaha has had a slow oil leak forever. It seems to be from the seam between case halves. I’ve tried rtv and other various sealants, no luck. Right now I have The right stuff in there, there is a groove there that was cleaned real good before application. Just a few drops after riding while engine is cooling. Can’t JB weld it or anything permanent in case it has to be opened up someday. Any ideas to stop this?
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