Sportster Cafe Racer by Ardent Motorcycles

Sportster Cafe Racer

Today, we’re proud to feature one of our favorite Sportster builds of all time:  The Cafe Sportster, built by Curtis Miller of Ardent Motorcycles.  Curtis has one of the most interesting backgrounds of any builder we’ve ever featured.  He was trained as an artist, with a BFA in painting. He’s been self-employed since he was 24, first as a custom furniture maker, later as a computer animator. He’s sold his paintings and photographs through art galleries, and does the photography for his own bikes. He’s built a classical guitar, several electric guitars, a wooden kayak, many radio controlled gliders up to a 15′ wingspan. Now he makes motorcycles. Here’s what he says of his history on two wheels:

My history with bikes is amazingly short. I only started riding five years ago, at the advanced age of 56. I started on a Harley Sportster and moved up to a Softail Slim within the year so I could travel longer distances and take my fiance with me. I loved riding immediately. I couldn’t get enough. I rode almost every day during the summer, and couldn’t resist riding in the winter sometimes as well.

Harley Sportster Cafe Racer

Within a year, I started customizing my bikes. The following year I started my first full custom build. For the last couple of years I’ve been building full time. When I started, I had absolutely no mechanical background at all. I knew how to use tools of course, but had not even changed the oil in one of my bikes when I started. I started teaching myself how to work metal and weld, how to use an English wheel and a mallet and shot bag. Before long, I got to the point where I needed help and advice. I found an excellent motorcycle program at Washtenaw Community College. They gave me the depth of understanding of the mechanics of motorcycles that I needed. I also took welding and machining and metalshaping classes there. At this point, I’m a certified mechanic and I’m still taking advanced classes in engine building and dyno operations and tuning. I went there intending to take classes in bike building, but by the time I took all the prerequisite mechanical classes I had already taught myself to build.

Cafe Sportster

My workshop is a converted two car garage. I added insulation, drywall, and heat so it’s quite comfortable. It’s packed with machinery and tools and bikes, but it gives me enough room to build. I have a lift, a small lathe and mill, a drill press, a tig welder, blast cabinet, buffers, sanders and grinder, an English wheel and all the hand tools I need. I do all of my own fabrication and painting as well. I could use twice the space, but I like the convenience of working from home.

Harley Sportster Cafe Racer:  In the Builder’s Words

This bike is a completely custom build from the ground up. I built it in 2015. It was based around a 2009 Sportster engine I bought from a salvage outfit on ebay. The build took a full six months. I designed and built the frame, the aluminum tanks, the swingarm, the rearsets, exhaust, and many other small parts.


I built this bike for myself, but I always had at least half an eye toward building bikes professionally. It wasn’t until I finished the bike and saw the reaction to it that I got the nerve to try building commercially. As soon as I took the bike out I got a great reaction. At the very first gas stop, a crowd formed before I could even get the gas cap off. I’ve literally had crowds form almost anywhere I stop. I’ve customized several bikes at significant effort and expense but none of them ever got a fraction of this much attention. I’ve had people on bikes turn around and follow me, people come up to me in restaurants. It was amazing.

The Concept


I built this bike entirely by myself. I used no outside services other than getting the logos 3D printed. I bent the tubes and welded the frame. I made the head tube from steel pipe. I aligned it on my home made frame jig. I made the engine mounts. I fabricated all of the tanks by hand, welded them and sanded and polished them. I built the electrical box (under the seat) from aluminum sheet and even welded up the swingarm from flat stock. I painted the frame and electrical box (under the seat). I also wired the bike, starting with a Sportster wiring harness, cutting it to pieces and reassembling it. I made the gas and oil caps, the timing cover, the rearsets, everything.

My first build was a classic chopper with a raked springer front end and a hard tail. You have to remember that I came from the Harley-Davidson world. It was awful to ride. Harsh on the backside and almost unmanageable at the front end. When I finished and rode the thing, I decided right away that the next bike I did would be something with real, working suspension, something that handled well.


I had been watching the Cafe Racer TV show for years and loved the clean, compact, elegant forms of the cafe bike. That’s where I started. I decided on a modified featherbed style of frame and built everything around the motor. I bought a complete CBR1000rr front end and shocks for the rear. I kept the rake and carefully checked the trail to make sure the handling would be correct. It handles very well with no instability, even without a steering damper.

Everything that I could, I built from scratch. I own the book the Art of the Racing Motorcycle. The rough, racy simplicity of those bikes was a big inspiration as well. That’s probably where the rough looking swingarm and the “racing” number on the electrical box came from. I loved all of the little levers and caps and adjusters that those bikes had

The Parts


Commercially purchased parts included the engine, front end, rear shocks, wheels and tires. The wheels are Chinese made wheels intended for a CBR1000rr. The rear shocks are brake rotors are also Chinese made. I was building this bike out of my pocket so I had to economize where I could. Any of those parts could easily be replaced with brand name parts very easily. I bought a couple of small dress up covers for the air cleaner and clutch cover. I’ve since replaced the air cleaner for one that breathes better. The lighting include a headlight Dime City and led lighting for front turn signals and rear brake/run/turn signals. I didn’t want big clunky lights handing off the bike anywhere.

Favorite Things

I’m probably most proud of the way the overall build hangs together. I think it works as well as it does because of the proportion of the bike; the way the electrical box (remember, this is a fuel injected bike with a lot of wiring!) fits under the seat, the proportions and shapes of the gas and oil tanks, the rough and ready looking swingarm and exhaust pipes. The tank at the rear of this bike is a functioning oil tank. The Sportster has dry sump oiling with a tank normally located under the seat. I needed that space for the wiring, so I made the rear tank a working oil tank. It has cool copper lines running down behind the electrical box that add a nice look from the rear.


On the level of the fabrication work, I’m proudest of the frame and tanks. This was my first attempt at a polished aluminum tank and I was not sure that I could do it when I started. It was a tremendous amount of work and not at all easy, but the results are really nice. I loved the process despite the difficulty. I love the real hands on fabrication involved. Those tanks are the heart of the bike.

The frame is also pretty complicated. The Sportster’s rear engine mounts are offset from the center line of the engine, so the rear of the double hoops are not symmetrical. It was very tricky to locate the engine correctly and build the asymmetrical frame and the electrical box. The welding on the frame is beautifully finished. I used no filler on this frame at all. What you see is solid metal. I welded first, sometimes using silicon bronze applied with a tig torch as a filler, then grinding smooth. It’s super clean and smooth looking.


I’m also proud of the rear sets. I designed those and milled the parts by hand and they work great. The brake pedal assembly is mounted on hand made standoffs that bolt into the engine using holes that were for the lower rear engine cover. The shift lever design is my own and it is very sharp and positive. Feels much better than the clunky stock Harley shifter. It’s cleaner and less complex than other designs I’ve seen. The parts were milled by hand or turned on the lathe by hand. No CNC work.

I have a web site, which includes some blog entries from me and a lot of build photos of this bike and another more recent one. I’m also on Facebook at Ardent Motorcycles. There are tons of daily build photos and comments from me there. If you want to see what it’s like to build a bike like this on a daily basis, this is the place to go. I’m also on Instagram as @Ardentmoto.

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