Pour it up, Pour it up.  Rihanna's balling out with Young Jeezy, Rick Ross, Juicy J. and T.I. for her brand new remix.  Check it inside, plus why her tour buses got stopped at the Canadian border today....

As Rihanna just wrapped up two nights in Toronto on her Diamonds tour, she's letting the fellas take over her "Pour It Up" track for the official remix.  

Young Jeezy's up first on the track, then Rozay pops in with a few bars, Juicy J. adds his strip club flow to the newest strip club anthem, and T.I. closes it out trap style.  Rihanna's hook stays in tact.

Check out the "Pour It Up Remix" below:

Not gonna lie.  This remix BANGS.  We like it better as a rap track with Rih on the hook.

Meanwhile, Rihanna's 10 tour buses were crossing the Canadian border into Detroit today (ahead of her tour stop in the D tomorrow) when they were stopped.  All because border patrol smelled...you guessed it...weed.

TMZ reports only a "small stash" (the real shocker) was found on one person after a bus-to-bus search with drug sniffing dogs.  The fella who was caught received a "civil penalty" citation.

It's all good though.  Rihanna wasn't on any of the buses....and she still got her money.