Analysis of information sources in references of the Wikipedia article "Streetfighter (motorcycle)" in English language version.
Streetfighter -- Also known as a 'hooligan' cycle, this is a sports-bike stripped of all superfluous bodywork.
streetfighter: a type of superbike customized for maximum speed and performance.
[In London in the early 1990s,] I noticed an odd-looking motorcycle idling loudly across the crowded intersection. The bike's upside-down front end was topped by a pair of oversized headlights that appeared to have been stolen from a car. The rider's gloved hands clutched a set of what looked like handlebars from a motocross bike, while the exhaust can -- or what little remained of it -- was burbling like a beehive on fire.
Was this a prop from Mel Gibson's Road Warrior? Some poor motorcycle courier who had dropped his machine so many times that he'd refused to replace his damaged fairing? [more]
...examples of the style began showing up almost by accident (pardon the pun) on the stunt riding scene early on. Just as many European riders had crafted naked bikes out of crash-damaged sportbikes, many American freestyle riders simply came to the conclusion that their CBR 900RR would ride better on one wheel with the fairing removed, the clip-ons traded for a set of tubular bars, and a custom bent exhaust pipe that didn't scrape on the pavement during wheelies.
The origins of the species are disputed. Some say that the Germans put high-bar conversions on sportbikes to lessen the soft tissue damage of the annual high-mileage pilgrimage to the Isle of Man for the TT races, and these were the first streetfighters. Others say -- and I agree -- that young British GSX-R riders removed their bike' fairings after crashes. They were already up to their Simpson Bandits debt to buy the bikes; they still owed three years of payments and dared not claim on the insurance for fear of having their policies loaded to the point they were priced off the road. The situation wasn't helped by the Japanese firms' replacement-parts pricing structure making new bodywork out of the question. And the old oil-cooled Gixxer Four is just about the best looking Japanese motorcycle ever, so why not show it off?