These words are examples of primitive onomatopoeia used by Chavs or the like, when making noises like guns.
Apparantly "brap brap" sounds like two rounds being fired. However i think not.
Harry the Chink
(whilst in Miniman's Corsa SXI: "Brap Brap i drive by dat nigga"
Crazy Joe: "Shut your gob you stinky Chink
The sound made when you see someone wearing a fox racing or other dirt bike sponsored apparel. Used in place of a greeting.
brap brap fox racer, what are you up to tonight?
Also means, ya alright
Brap-Brap Nizzle how it hangin?
Another name for a dirtbike, snowmobile, quad, or any toy with a small displacement engine. Also can be used with any number of a's to describe the sound of one of these toys in uses...
Expl.1) Hey bro, go grab your brap brap and let's go to the gravel pit and ride!!!!!
Expl.2) He came around that corner before the triple and he was like "brap brap braaaaaaaaaaaap!"