Tyga's Kanye Music Label Deal Not a Kardashian Gift

Tyga's new deal with Kanye's G.O.O.D. Music isn't a favor to the Kardashians -- we're told Kanye legitimately digs his music.

Sources close to the rappers tell TMZ they've worked together on music for years, and signing Tyga was strictly a business decision. Although Kanye is clearly all-in with the family on all its ventures ... we're told the Kardashians did NOT cross the line into his music world.

As one source put it, Kanye doesn't take on ANY artist or project he doesn't believe in personally.

Plus, there's a genuine friendship between them -- we're told 'Ye and Tyga started teaming up way before Kylie was in the picture. In fact, Tyga was with Blac Chyna when they started, and that's how she and Kim became friends.

We're told Tyga's been hitting the studio a lot with Kanye lately, and will be featured on the G.O.O.D. Music album, "Cruel Winter," which is supposed to drop next year.