Casper Smart SLOW YOUR ROLL!! Gets Probation for Drag Racing

1/3/2012 4:20 PM PST

Jennifer Lopez
might want to think twice about handing Casper Smart the keys to her Bentley ... 'cause her BF just pleaded no contest in a drag racing case.

Casper's high speed bust came back in April 2010 -- long before his J.Lo days -- and today an LA County Superior Court judge hit him with 12 months probation and a $500 fine.

Casper wasn't required to be in court ... his attorney entered the plea. We're guessing speed racer had better people things to do.