Mendoza GSX-R - New World Order

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Words: Dave M pics: Seb Seebacher

Quite astoundingly, there are still a great number of people who believe that the only custom motorcycles being built in the good ol' US of A are either massive capacity air-cooled vee twins of domestic origin, or Japanese sportsbikes slung lower than a snake's belly and with a back tyre fatter than both of Kim Kardasian's arse cheeks put together.

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But, quite frankly, that is an opinion that is so outdated that it can be found in the Old Testament. The truth is that the custom bikes being built in America are actually as varied as in any other country on this little blue planet of ours – choppers, street racers, flat-trackers, lowriders, diggers, bobbers, cafe racers, supermotos and, yes, even streetfighters are being created in sheds, garages and workshops throughout the fifty states.

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Some of those are being built by people who've been building streetfighters for ever, some builders have been and gone, while others have only recently discovered that custom bikes are cool, and that custom bikes built with love and passion and with a focus on reduced weight, increased power and improved handling (yes folks, that's a streetfighter!) are cooler than week-old penguin piss.

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Sebastian Seebacher is a relative newcomer to the world of streetfighters, yet in his short time of building performance customs he's already made his mark. You'll no doubt remember his VFR750 'fighter that we featured in WWB#8, a bike that Seb built for himself, but his next project was a customer build.

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The donor bike was a 1990 model Suzuki GSX-R750, the sweet-handling pre-water-cooled Gixer 750 that is often the base bike for the popular 7/11 conversion using the big brother Gixer's 1100cc engine. This time, however, the bike kept the original powerplant. This may seem a little tame, but you have to remember that the 750 lump is capable of 100bhp in standard form, and with it's sweet power delivery and six speed transmission it is, for many people, more fun to ride. Seb equipped the engine with a set of free-flowing stainless steel 'sidewinder' header pipes, which pass the burnt combustion gases into a one-off linkpipe and henceforth to a Yoshimura end can. The original airbox was junked, so the standard carbs now wear a set of K&N filters and were treated to a total overhaul including a set of Factory Pro jets.

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Unlike the bigger engine's hydraulic clutch actuation, the '90 model 750 has a cable clutch operated via the clutch cover, meaning that the sprocket cover has no clutch actuation points, so can be unceremoniously fucked right off. This looks far racier, and saves weight. No brainer.

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The original bike's portly posterior was swiftly disposed of, courtesy of some heavy duty cutting equipment, and a Yamaha R6 subframe brought in to take its place. Naturally, this wasn't a straight bolt-on affair, and the Yam subbie had to be shortened by three inches at the front, with the end result having the top of the pillion seat perfectly aligning at the same height as the top of the standard fuel tank, which itself had to have a new rear mount made thanks to the new subframe. The angular R6 tail is neatly matched by more Yamaha bodywork at the front, in the form of an MT-03 headlight and surround.

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With the aesthetics sorted, thoughts turned to the handling, and the options of upgrading not only to better quality suspension, but also modern radial brakes. All of this came in the form of forks, wheels, swinging arm, disc and calipers from a K7 model GSX-R Thou. The yokes from the 1000 were also used, albeit with the original steering stem from the 750.

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With a complete and rolling machine, Seb stripped it all back down into its component parts so that it could all be painted and all the detailing undertaken. And it's the attention to detail that makes the difference between a run-of-the-mill bike, and a piece of two-wheeled confectionery – sweet as!

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So, the frame was powder-coated gloss black, along with the yokes and swinging arm, the bodywork has the neat two-tone silver and white applied, with the colour scheme even extending to the rear hugger. The engine was fitted with a pair of billet crank covers, and a twin line breather fitted into the clutch cover with braided hoses leading to a one-off breather tank that's mounted onto the bespoke oil cooler brackets which carry the 'Sebspeed' logo – the name for which Seb has allocated himself and which is his moniker on the Custom Fighters forum. A few anodised goodies - in the form of the rearsets, engine oil filler cap and bar risers - add a bit of bling, while velocity, engine revolutions and various other readings are shown on the Koso DB03R clock.

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Since completing the GSX-R, Seb has also built a big bored CB900 for himself, and is currently mid-build with a VFR800 for a customer, as well as converting shit-loads of clutch covers and fitting perspex windows in them. He's a busy fella, so watch this space for more of his creations!

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1990 GSX-R750, carbs cleaned & rebuilt with new rubber, Factory Pro Stage 3 jet kit, K&N filters, stainless sidewinder header, feeding custom midpipe & stainless Yoshi R55 pipe, CX Racing oil cooler, Earls fittings & hoses.

1990 GSX-R750, gold anodised rearsets with standard rear brake master cylinder, 2012 Yamaha R6 subframe shortened 3" at front.

Front end:
2007 GSX-R1000 forks, triples (w/ 750 stem), swinging arm, shock, wheels
Top triple ignition delete, ignition moved to right rear motor mount
Flat drag bar, Chinese adjustable levers, Pilot Power tyre, '08 ZX-10R brake master cylinder, Russell stainless front lines, '06 ZX-10R clutch master cylinder, '07 ZX-10R kill switch, '15 Hayabusa left switch pod.

Rear end:
GSX-R 1000K7 swinging arm, shock, wheel, disc & caliper, Core Moto stainless braided brake line, Pilot Power tyre.

Rear tank mounts modified to fit on custom mount bracket, 2012 Yamaha R6 tail unit with Chinese solo cowl, smoked & integrated taillight.

Original loom modified to suit new tail, gauges & switches.LED licence plate light.

Paint & polish:
Full respray in silver / white, frame, yokes etc powder-coated gloss black.