The rapper says Dave hopped on a jet to come see him "doing well" on the ranch, and called him a "God send and a true friend." The great, warm, friendly visit did come with one slightly awkward moment.

Kanye got Dave, and a few other friends there, to gather around for a video ... and then put the comedian on the spot to come up with something funny -- y'know, to make everyone laugh.

It was, apparently, pretty early in the day, 'cause Dave said he wasn't in funny mode yet, but watch ... of course they found their way to a punchline.

As we reported ... Kanye went on a wild rant Monday night, firing off several tweets that accused his wife, Kim Kardashian, of trying to have him involuntarily committed to a mental hospital.

He also blasted Kris Jenner for allegedly influencing some of Kim's past career moves -- i.e. posing for Playboy and selling her sex tape -- and compared his life to "Get Out."

Assuming Dave touched down in Wyoming Tuesday morning -- as Kanye inferred -- he went pretty far out of his way to help his buddy. We're told Dave's been doing "invite-only" comedy gigs near his home in Ohio.

Dave flying out couldn't come at a better time for Ye -- as we've told you, many people close to him say he's in the midst of a serious bipolar episode.

No such thing as a bad time to chill with Chappelle, but this is a particularly good time.