You know how the sounds and stimulation of a city can overwhelm your senses? Its details blur together until something out of the norm happens — someone with a special sort of vibe grabs your eye. You pause and stare, perhaps for a little too long. They are hiding something, you can just tell.
That’s the feeling that washed over me when I came across Derek’s Yamaha XJ750 Maxim, aptly named Turbo Maximus. I’m not super confident in my motorcycle-hunting skills and, honestly, I know very little about the various bike scenes in general. Basically, anything remotely unique will impress me, but there was something extra special about this XJ.
After contacting Derek to get the details, I found out I wasn’t wrong.
Originally a black 1982 Yamaha XJ750 Maxim, this motorcycle is the first and only one Derek has ever owned. But why this particular bike? Derek says he has always been drawn to Japanese race bikes, particularly the 1984 XJ750R (0U28) racer that ran in Japan for the 1984 Suzuka 8 Hours — the only XJ-series bike Yamaha ever raced.
If you aren’t familiar with this era of motorbike racing and you’re itching for some knee scraping and gutsy speed, check out these highlights from the ’85 race on the ol’ YouTube. Fair warning: once the music starts, this video contains an ’80s cheese factor of 100.
Cheese aside, Derek has managed to capture the exhilaration of the sport in with his own XJ by utilizing his engineering and (largely self-taught) fabrication skills.
It’s all the better, too, as there’s something extra special about builds that are done entirely by their owner. We get to see the artist’s final product exactly as they envisioned, no middlemen or shortcuts.
The Yamaha XJ750 was reborn in Bryan Fuller’s shop Fuller Moto — which we will give you a look around soon — in Atlanta, Georgia. The way Derek and Brian’s relationship began is somewhat of a story in itself, but an abridged version would read something like this: Derek got an engineering degree after leaving the navy, he had been a fan of Fuller’s work, so while in the limbo between school and a job he decided to take a leap and send a thoughtful email to the business owner.
The rest is history; their relationship proved to be mutually beneficial with Derek taking on work at the shop, also using the space to produce the beauty you see today.Race Feel
So, what did Derek do to the bike? First and foremost he did something most people doubted was possible.
Derek transformed the old Yamaha into a modern superbike. Turbo Maximus: sharp, tight, fuel injected and boosted, a seamless homage with enough innovation and individuality that you forget the original XJ750 Maxim it was born from.
This was accomplished in part by tackling something few have previously done: converting the carbureted setup to EFI. Although EFI swaps are nothing new, most of these conversions are done on cars so there was no kit nor instructions nor guidelines for DIY-ing it; Derek had to pave his own way.
He did exactly this by Frankensteining a MS3 PRO ECU by DIYAutoTune with GM truck coils for each cylinder, managing to neatly hide the piles of wires and sensors that are associated with the switch-over. The bike now makes use of an AiM MXS dash, a nice modern touch with has GPS speed and position tracking built in.
Because Derek put his own heart and mind into the swap he has complete understanding of (and control over) the hardware and software for timing, fueling, ignition and turbo settings, something he wouldn’t get if he had outsourced the labor.
When it comes to the heart of Turbo Maximus, Derek chose to exchange the original 750cc engine with its bigger brother, the XJ900. The four-cylinder was poached from an ‘83 and rebuilt by NASCAR engine builder Jordan Hersey. I told you, the bike just keeps getting more special.
With the big engine to play with, Derek was highly calculated and design-oriented when it came to choosing the turbocharger. He wanted it to look streamlined and unified, as if the bike was originally equipped with one from the factory. To avoid having the boost-builder look like a poorly placed afterthought Derek needed to choose a turbine small enough to be neatly tucked away, but still large enough to allow him to hit his 200hp goal (on E85). Ultimately a BorgWarner S1BG checked all the right boxes.
Have a listen to the absolutely glorious end result of Derek’s scheming and dreaming with the 900 cackling out a slip-on titanium Akrapovič muffler. And don’t mind the front end lifting on acceleration…
Continuing on, in order to have Turbo Maximus ride and feel as he envisioned, Derek converted the rear suspension from a dual rear shock into a five-way adjustable mono-shock. At the same time, up front he made use of a 2015 Yamaha R6 suspension setup with Traxxion Dynamics AK-20 cartridges and an adjustable steering stabilizer by Öhlins.
To ensure that the wheels and tires made sense with the bike’s makeover, Derek brought over a rear wheel from a European XJ900S which was then widened from 4 inches to 5 to allow a fatter rear tire. He wrapped it up with Metzeler Racetec RR K2 rubber (120/70ZR17 in front, 160/60ZR17 in the back).Race Look
Beyond the extensive mechanical overhaul, the XJ750 turned turbocharged 900 is a truly beautiful machine, a place where function smoothly meets form. The body of the bike is in fact original, although Derek has custom-tailored loads of details to make it match his initial vision.
He fabricated the tail section and swing arm for the Yamaha himself, with coordinated customizations that follow from rear to front.
To get the front end look he wanted, Derek heavily modified a replica F1 front fairing by Airtech Streamlining to fit the bike. He widened and pulled the fairing back from the windshield area, fabricated aluminum fins which were riveted along the bottom of the fairing, handmade a custom aluminum bezel headlight housing, and finally added a custom-built windscreen from Gustafsson Plastics.
The list of modifications the bike has gone through is towering, but in itself it doesn’t include the countless hours and all-nighters in the shop which resulted in the truly brilliant creation Derek owns today.
The lengths enthusiasts go to achieve their vision never ceases to amaze me. Whether it’s a vintage race-inspired Japanese motorcycle or a custom lowrider, those who are addicted to things with wheels can’t seem to rest until they reach their goal, no matter how lofty that goal is.
No stone was left unturned on Derek’s bike and I think we can all agree that the final product was worth his enormous effort, even if Turbo Maximus is so well-executed that it in fact looks effortless.