Justin Bieber -- FERRARI Outlaw Pulled Over by Cops

7:20 AM PT -- Law enforcement sources tell us ... Bieber was initially pulled over for making an unsafe left turn. During the stop, we're told the officer discovered Bieber's registration was expired.

Justin Bieber's winning streak came to a screeching halt when he went joyriding in a Ferrari Tuesday night ... and got stopped by cops, TMZ has learned.

Justin was cruising through West Hollywood around 6:30PM in a sick white Ferrari when an LA County Sheriff's deputy hit the strobes and sirens.

TMZ got a couple shots of the Biebs as he was pulled over. Witnesses say JB was cooperative while deputies took a closer look at his documentation ... and, of course, the sick ride.

Law enforcement sources tell TMZ Bieber did get ticketed, but it's unclear what law he allegedly broke.

Bieber's coming off a hell of a weekend -- hanging with Victoria's Secret supermodels, and breaking up with Selena Gomez. Justin was NOT solo in the Ferrari ... we're told he had a guy friend riding shotgun.

Bieber blasted this pic over Instagram -- proving the side view mirror of a Ferrari can even make cop car lights look cool.

We've called Bieber's peeps ... but no word back yet.