Before you ask any questions, here's our answer to all of them: We have no idea.
We don't know who this man is, other than the fact that the vid refers to him as The Brave Pathan of Karachi, which means he's likely from Pakistan. We don't know for sure what he is riding, but it sounds like it may be a single-cylinder Honda (or one of its many clones).
Why is he shooting off his gun? Dunno. We can't say for sure what language the men are speaking, either, which means we have no idea what they are saying. We imagine they are congratulating Mr. Brave for his amazing stunting skills.
Well, there is one thing we do know: This video is awesome, and for all the wrong reasons. Revel in all that is unknown in the video after the break.