AN-BU Motors builds a Custom World street racer…
As a young man, Koichi Fujita of AN-BU Custom Motors was a driver in the Formula Race/FJ1600 and F4 series held at Suzuka Circuit, where he won a championship. After that, he worked in race car fabrication and engine tuning, and also learned sheetmetal work and painting from his father before opening his own workshop in Nagoya, Aichi, Japan:
“It is said that the Fujita family has its roots in the Anbu family, a warrior family from Hagi, Yamaguchi Prefecture, who served the Mori family, which ruled the west part of Japan region during the Warring States period about 500 years ago. To clarify these roots, he named his workshop AN-BU.”
Since then, Koichi has been building various styles of custom bikes with rock, punk, and racing spirits — sometimes known as “AN-BU style” — and has developed a strong fan base not only in Japan but all over the world.
Recently, Royal Enfield asked him to build a Continental GT650 for their Custom World series, which gives the world’s best builders a donor bike to customize according to their own style and vision. As Koichi is a regular at the track, both racing his own bikes and building them for others, he wasn’t so sure at first about building a custom that would be launched and featured in a series of custom motorcycle shows:
“I don’t think a bike built for a show is cool. So I thought that this request from Royal Enfield was a little out of my usual approach to bike building. So, I decided to build a bike that would combine Royal Enfield’s wishes with AN-BU’s usual style.”
AN-BU bikes are influenced by the endurance racers like those that competed in the Suzuka 8 Hours starting in 1978, and they have the gritty, hand-hammered style of real riders and racers, not show queens. For this build, Koichi envisioned a kind of retro-inspired street racer:
“I imagined a racing machine that was used on the track in the 1970s to 1980s, but modified so that it could be ridden on open roads.”
The bike is now running conventional 38mm Kayaba forks with one-off billet yokes, YSS X-Series rear suspension with custom mounts / subframe, bespoke aluminum tank and tail, bespoke carbon fiber fairing with offset headlight (an AN-BU signature), and a custom steel exhaust:
“The headers inside the cowl have a complicated layout, like a snake coiling around a spike, to make the pipes longer. However, I…placed them in such a way that they protrude only slightly from the cowl. It is good to show just a glimpse of it.”
The bike’s nickname, “Kai,” is a shortening of the term “Kaizo,” which means modification — this word, says Koichi, was the one he and his compatriots used when they were modifying bikes as teenagers, before the term “Custom” grew to replace it.
Kai is one of the most striking Royal Enfields we’ve seen — a bike that’s instantly recognizable as an AN-BU build, and as Koichi intended, looks as good with a rider as without. A special thanks goes out to our friend Tadashi “Tad” Kohno for bringing us the following interview, and credit goes to Keigo Yamamoto (@kgo106) for these stunning photos. Enjoy!
Builder Interview: Koichi Fujita / AN-BU Custom Motors
When Royal Enfield’s HQ invited me to participate in their customization program “Custom World,” I was asked to build a custom bike based on the Continental GT650; it didn’t click with me at first.
Of course, I’ve been presented with the specific condition of the project and had seen the work of the other builders who participated in Custom World, so I understood what kind of program Custom World was. But I had no idea what kind of custom bike I should build as AN-BU. I thought about that for a while, but the guys at Custom World saw AN-BU’s past works and approached me. So, I decided to build a custom bike that would be just like AN-BU’s without changing my style.
I had decided on the style of the custom bike I was going to build, but they said that my custom bike would be launched and exhibited at the 2023 motorcycle shows in Osaka, Tokyo, and Nagoya. However, I don’t think a bike built for a show is cool. So I thought that this request from Royal Enfield was a little out of my usual approach to bike building. So, I decided to build a bike that would combine Royal Enfield’s wishes with AN-BU’s usual style.
A very important concept to making my custom bike is to create a bike that looks cool on the street when ridden by a rider. That’s why, for this project, I decided to build a bike that I think is cool to ride, even though it will be launched and exhibited at a motorcycle show in Japan. I put everything I could do now into this bike, and this is what I ended up building with my passion.
I named this bike “Royal Enfield – KAI”. When I started to customize bikes as a teenager, we did not have the word “custom” but called it “KAIZO” (it means modification). I modified it to the shape I envisioned. So, I named it “KAI” with to express my origin.
What I wanted to express with “Royal Enfield KAI” was a sense of speed. To express this, I wanted to create a form like a racing machine. However, what I envisioned was not a racer running on a track, but a racer running on the street. Moreover, I imagined a racing machine that was used on the track in the 1970s to 1980s, but modified so that it could be ridden on open roads.
Important to this style is the shape of the fuel tank. It’s long, thin, and composed of lines that are beautiful from any angle. To achieve this, the shape of the frame supporting the fuel tank is also important. Therefore, I reconfigured the layout of the upper part of the main frame and the rear frame to resemble the frames of racing machines that were active in the 1970s to 1980s. However, the steering head area, engine mounts, swingarm pivot points, and swingarm itself remain standard.
The front fork is a 38mm Kayaba inspired by the racing machines of the ’80s. The triple tree was machined from aluminum block. When making it, the fork pitch and offset were set for sport riding, which together with longer fully adjustable rear suspension makes the handling ideal for me.
On the carbon cowl I built for KAI, I placed the headlight in a location offset from the center of the front cowl, as is standard on AN-BU’s custom bikes. The image source for that was also from the endurance racers of the ’80s.
I designed the layout of the exhaust headers, the shape of the cowl, and their placement with great precision, so that the pipes would be slightly visible through the cowl.
The headers inside the cowl have a complicated layout, like a snake coiling around a spike, to make the pipes longer. However, I did not dare to show them, but placed them in such a way that they protrude slightly from the cowl. It is good to show a glimpse of it.
I did not want to show the carbon weave in the cowl, so I’ve painted the surface matte black, finished in an exquisite shade that shows the weave of the carbon depending on the intensity of the light and the angle of view.
The fuel tank and seat cowl, which were made from aluminum plate, were left to show the hammered surface as it is. I think it would be unnatural if the surfaces were evened out to a shiny finish. The bikes I build are designed to fit in with the city and to look good on the street.
Of course, I am also interested in the latest racing machines. Especially since their technology is always evolving, and their mechanisms are very interesting to me. Since I race on the track with my own bike, I want to incorporate new ideas and experiences into the creation of a bike, and I also want to evolve the bikes of my customers who are also racing on the track.
I am surrounded by tuning shops and workshops that have been supporting the forefront of 2-wheel and 4-wheel racing since I was racing as a driver, and I am able to share various information with them. I use this experience in the production of AN-BU’s custom bikes to consider the concept and style of the bike and the parts that make it up, from the perspective of both riding and appearance.
A bike that is fun to ride. This is the core of AN-BU’s custom bikes and will never disappear. And I was able to realize it in this “KAI” as well. That is how I feel.
Build Sheet: Royal Enfield “KAI”
■Model Name： Royal Enfield – KAI
■Donor Machine：2021 Royal Enfield Continental GT650
・Exhaust Headers：One-off by Steel
・Exhaust Silencers：One-off by Steel
・Main Frame: Standard / only top tube was modified
・Rear Frame: One-off / the mounts of rear suspension on rear frame is modified
・Swing Arm: Standard
・Front Fork: KAYABA 38mm Telescopic
・Triple Tree: One-off / Billet Aluminum
・Rear Suspension unit: YSS X-Series
・F Master Cylinder: NISSIN
・F Brake Caliper: Brembo 4pot
・F Brake Disk Rotor: 320mm Single Disk
・R Master Cylinder: Brembo
・R Brake Caliper: Brembo 2pot
・R Brake Disk Rotor: 220mm Single Disk
・Front Wheel: 2.50×18
・Rear Wheel: 3.50×18
・Tires: PIRELLI / PHANTOM SPORTCOMP
・Front Size: 110/80-18
・Rear Size: 150/70-18
・Fuel Tank: One-off／Aluminum
・Rear Cowl: One-off /Aluminum
・Rear Fender: One-off /Aluminum
・Seat: One-off / Leather
・Foot pegs ＆ Pedals: One-off
・Headlight: No Name
・Rear Light: Kellerman
・Blinkers: Kellerman / Bullet Atto
・Meter：MOTOGADGET / Chrono Classic