Sportbikes of old were modest...
Sportbikes of old were modest when it came to showing off the goods—you’d never know there was a ‘Busa motor under there.
Poking a bigger motor into a vehicle is as American as apple pie on the 4th of July. Early hot-rodders popularized the trend of motor swaps and it naturally spread to the streetbike scene. Although modern sportbikes are compact featherweights, their ancestors were portly with spacious cockpits and even roomier frames that easily accepted big-displacement motors. They are the perfect platform for a two-wheeled hot-rodder aiming to build a classic sleeper.
Into this culture stepped Steve Patterson, mild-mannered Firefighter by day and raging performance bike freak by night. Patterson’s former bike was a twin turbo Suzuki B-King built big, loud and in your face. His latest bike however is as subtle as an Ivy-League suit. This old school GSX-1100 looks as staid as a bike that big can, but this hybrid is sporting a Gen. 2 Hayabusa motor between its rails. Why bother tuning an old 1100 when a modern 1300 can take its place? But swapping in the big bird of a motor was no easy task.
Gixxers just don’t sound like...
Gixxers just don’t sound like they used to and we have emission laws to thank for that.
The 2008 Hayabusa engine is not only heavier than a Gixxer Eleven’s oil boiler, but it’s also taller, hence the need for Patterson to alter the 1991 GSX-R1100M frame by removing the fixed lower engine cradle to make a pair of new bolt-on replacement steel frame members along with a new rear engine mount. Patterson’s other mods consist of handiwork hidden under the stock ’91 bodywork, which was widened by 2.5-inches at the belly to accommodate the beefier motor.
The original Gixxer tail unit and gas tank complete the street-sleeper persona, although the tank has undergone major internal surgery to include both the stock ’Busa fuel pump and a row of baffles that Steve welded in place to prevent the fuel from surging away from the pump’s pick-up pipe under the ferocious acceleration. Making the acceleration as fierce as an ex-girlfriend’s temper is a list of the usual suspects: a set of 1441cc big-bore barrels, 13:1 high-compression pistons, WEB camshafts and Carpenter valve springs. An Innovative Machine deep sump helps prevent the oil pump from gulping air instead of the brown stuff when the other engine mods are worked hard. Meanwhile, a Dynojet PCV handles fuel delivery and a full Yoshimura exhaust system assures you know the hybrid is hovering close by.
She’s so foxy! Some faces...
She’s so foxy! Some faces just get better with age.
Keeping tabs on a stock 2007 Hayabusa rear wheel is a pair of TJ Hoffmeister (wasn’t he on Baywatch?) drag racing bead locks that not only prevent the rubber from spinning off the rim but also allow for a wider 200-spec Bridgestone tire. The ménage á trois of ’Busa wheel and 1100 rear shock is completed by a 4-inch over Trac Dynamics swingarm. Up front a pair of 2009 ’Busa fork legs were modified for quarter mile spurts by Pit Tech instead of the low buck, but effective lowering strap. As for slowing the beast, a single ’Busa radial mount four-piston brake caliper was carefully lightened to match the slightly oversized front disc.
Aesthetically the combo is a winner to everyone but an air/oil cooled Gixxer aficionado since the featureless ‘Busa engine can’t compare with the fine lines of the original 1100M’s finned 1052cc motor. The Hayabusa lump was designed to hide behind a fairing and is more of a double-bagger in the looks department. Although Steve has given the matter some thought and plans to machine some new inlet stubs so that the injectors will sit level with the engine, (like conventional carbs). He’ll also add a plenum chamber-style air filter “box” to make the ’Busa motor more visually appealing. It probably will, slightly, but as far as hardcore Gixxer fanatics are concerned, it’ll be like putting lipstick on a pig … albeit an extremely fast one that’s as unique as it is brutal.