Mike Tyson -- I Was Blindsided By 'Piece of S**t' TV Reporter

Mike Tyson just WENT OFF during a live TV interview -- cussing out one of the hosts while cameras rolled ... and Mike's rep tells TMZ Sports it's all because the guy "deceived" Tyson on the air.

It all went down on CP24 -- an all-news network in Toronto -- when one of the moderators asked Tyson if his recent endorsement of Rob Ford could hurt Ford because Mike's a "convicted rapist."

Mike was furious -- at first, he admonished the guy for being "negative" ... until he finally blew up on the guy -- saying, "You’re really a piece of s**t. F**k you."

Mike's personal rep tells TMZ Sports ... "Mike was there to promote his very successful 1-man show and we felt deceived, bamboozled by the reporter when he broke our agreement to focus on the show by going off-topic."