A Rebels bikie bashed a man over a motorcycle repair bill to save face in the eyes of other gang members.
Court documents said Bourne had helped the victim become a nominee in the Rebels Outlaw Motorcycle Club in 2013.
In October that year, the man crashed the motorcycle of another member, Michael Reece, causing a $16,000 repair bill.
But the victim could not afford to cover the cost, which Bourne felt brought him personally into disrepute in the eyes of members.
Police phone taps from November 2013 to February 2014 record Bourne making threats about the victim in both calls and text messages.
In one call to the victim, Bourne said: "Well you f------ crashed the bike you f------ made me look bad to this f------ club".
In other calls to the victim he said: "You wanted to be part of us but you're not even a man you weak f---" and warned him that "when I see you I'm going to kick your f------ teeth through the back of your head … you're going to f------ cop it bro".
Bourne, with the help of Reece, then lured the man to a meeting outside the outside the Wok It Up store on Hibberson Street.
Reece told the man he had lost his Rebels' colours because he had failed to fix the bike.
Bourne then punched the man to the ground and stomped on his head, fracturing his eye socket.
Phone intercepts then caught Bourne bragging about the attack, saying "I f------ kicked the f--- out of him in the middle of f------ Gungahlin in front of every c----" and that "It teaches him a f------ lesson".
Defence lawyer, Richard Thomas, told a Supreme Court sentencing hearing on Wednesday that his client had shown insight into his conduct, accepted responsibility, and shown remorse.
Mr Thomas admitted the attack had been "frenzied" and "vicious", but said the victim had suffered no permanent physical injury as a result.
The court heard Bourne had a $1000 a day cocaine addiction at the time of the offence, but had since returned negative results to drug tests.
He conceded a jail sentence was inevitable but urged Justice Hilary Penfold to ensure the non-parole period provided his client with a proper incentive for rehabilitation.
But prosecutor Emilija Beljic questioned the authenticity of Bourne's remorse and noted he had been on bail for drug trafficking at the time of the offence.
She argued Bourne intended to continue his membership of the Rebels and had refused to take part in jail rehabilitation programs.
Ms Beljic said the "vicious attack" had been on a "defenseless victim" in broad daylight in a public place after two months of threats.
Justice Penfold will hand down sentence later this month.