Ray J's Manager On 'Famous' Video: Kanye Better Watch His Mouth (VIDEO)

**WARNING: The above video contains explicit language.**

(TMZ) -- If Kanye West wanted to get under people's skin with his "Famous" music video ... it worked, and now he's got Ray J's manager on his a** ... making serious threats.

Ray was in downtown L.A. when we asked what he thought of his nude appearance in Kanye's vid. Watch this -- Ray doesn't have much to say, but his music manager, Wack 100, said a lot, and sent a message to West -- "Tell that n**** he a long way from Chicago."There was a lot more.

For reference ... Wack is the same guy who manages The Game, and knocked out Stitches with one punch last year.

Watch Wack sound off above!

Photo: Getty Images