Bam Margera recently found himself throwing down with a stranger -- a fist fight captured on camera, but Bam says he was simply protecting himself and friends ... TMZ has learned.
ICYMI ... the video shows the 'Jackass' star wailing on an unidentified man. The clip's making the rounds online and has many of Bam's fans speculating the face-off has something to do with a tattoo dispute Bam posted about Monday -- he's calling his latest ink job "highway robbery" -- but we're told this is an entirely separate incident.
Bam's manager Mike Quinn tells TMZ … the fight in question happened last week in L.