What is JUSTIN BIEBER THINKING???! 

His friend, LIL TWIST, was pulled over in his FISKER driving RECKLESS... again, and TMZ got these exclusive photos to prove it! 

Biebs, who turned 19 today and was topless this morning, wasn't reportedly asked for comment. 

From TMZ.COM and their story: 

Justin Bieber needs to rethink loaning his car out to Lil Twist, because his Lil Friend just got another ticket in JB's Lil Fisker Karma.

Law enforcement sources tell TMZ ... Lil Twist was just pulled over on the 101 Freeway by CHP because he made an unsafe lane change.  Deputies cut Lil a break on the lane change but gave him a ticket for tinted windows.

FYI -- it's the same tricked out Fisker Justin was driving when he was racing down the 101 Freeway last year, trying to shake the paparazzi.

And you'll recall, Lil Twist is the dude who got a ticket in Bieber's Ferrari on January 1 when a photog was struck and killed while shooting the scene.

JB is in London.  He should have taken the keys. 

Note: TMZ exclusive photos used under agreement with TMZ and with restrictions.