Outsiders Motorcycles transforms a V-twin weapon…
The KTM 990 Super Duke was one bad machine, a 120-hp hooligan’s dream with a chromoly trellis frame, 999.8cc LC8 V-twin engine, and high-spec WP suspension. It was nothing short of an action movie on two wheels:
“There is surely nothing more frenetic on two-wheels than the KTM 990 Super Duke short of sticking a nitrous kit, a jet turbine, and a flame-thrower into the frame of a fold-up bicycle.” —MCN
Enter our friend BertJan of Outsiders Motorcycles, whose Ducati Multistrada custom we recently featured. Back in 2020, we showcased a Husky Vitpilen 701 that he’d customized, and a prospective client, Julian, wanted something similar. However, at well over six feet tall, Julian was too vertically advantaged for a 701.
“He therefore decided that the Vit’s older and also bigger brother was the way to go.”
BertJan brought an ’06 Super Duke 990 into the workshop. The plastics were cracked, scratched, and rattle-canned black, so they went into the garbage as he envisioned a complete aesthetic transformation for the machine, whose bright orange Transformer-like factory styling was never its strongest suit.
He designed and built a new custom chromoly subframe, fabricated a new tank and tail section out of aluminum, and modified the bike to suit such a tall rider: longer forks from a KTM Adventure bike, higher seat, lower pegs, rear Hyperpro shock adjusted to match, and much more.
The result is a striking, highly capable daily rider with street tracker styling echoes. Painted Marrakech brown, we could easily see this machine at home among the beautiful palaces of the Moroccan city from which the color gets its name, as well as the sand-swept roads of the rest of the country. Below, BertJan gives us the full story on the build, along with more photos from Diederik and Lynn at Winchester Creatives.
KTM 990 Street Tracker: In the Builder’s Words
This 2006 KTM SuperDuke 990 came to us after a social media back and forth with Julian about customising a bike. We soon decided a bike that would stand out should be the plan and a full build was booked. Julian liked my work done to the Husqvarna Vitpilen 701 two years back, but as he’s well above two meter, that was no option. He therefore decided that the Vit’s older and also bigger brother was the way to go.
I started with taking all the plastics off the bike. I didn’t plan on re-using them — besides being cracked and scratched, they were also rattle-canned matte black, so in the bin they went. I also removed the original speedometer to find out if the bike would still run without it, which it did, and worked my way up to the initial design. I like to keep the designs rough and basic, because it leaves room for improvements and ideas along the way as long as the big picture is clear.
The 990 is not that high to begin with and keeping the seat height stock would clash with the owner’s knees and legs. I therefore opted for a heightened, floating seat. This keeps the bike visually low and light without sacrificing too much comfort. One of the other first things sorted was the stance.
The stock front end is quite low so a new set of legs was borrowed from the more adventurous 990’s brother. It makes for some serious height advantages over stock and the Hyperpro rear shock was adjusted to keep everything in spec. I made a rudimentary seat with pieces of wood to check height and geometry, and once that was ok’d by the client, I had the seat height and stance worked out. The actual framework could then begin.
The subframe was the first thing that had to go and after the frame was put into the jig, a new chromoly subframe was designed, machined, and tig-welded int place. Seat mounts and various other brackets were added, and I also made the seat pan out of 10mm aluminum. As it’s supported by only four rods, I wanted to be sure it was strong enough. I also wanted to make it before sending the frame out to powder, as fabwork easily scratches fresh coat. Better safe than sorry.
Footpegs were lowered a good 8 cm, re-using the old upper mounts and welding them back lower onto the frame. The stock lower mounts stayed on and are now the upper ones.
After the riding position was set in stone, I worked on a fuelcell design, as the stock one wouldn’t fit into the design I had in mind. The sides were made from cardboard first and then laser-cut to secure symmetry. The rest was cut by hand, as it’s just faster then going back and forth to the computer and cutter due to the organic shapes that occur when shaping them.
With the fuelcell ready, I started on the rear cowl section. Again, making it from cardboard first and then transferring it to aluminum. First one was binned. Found out the shapes I had in mind were tricky to do right the first time. So started over. The third one made the cut and was smoothed and shaved until I was satisfied with the end result. Fuelcell cover was next, same process but as I learned a lot from the tail, this was right the first time. The cover is bolted to the main frame with four bolts and gives access to air filters, electronics and battery if removed.
Fairing/fender combo was next and constructed just like the other bodywork parts. Cardboard first, traced, cut, shaped, welded.
I mounted the bodywork onto the frame and did some fast photoshops on it to see what colours would work. I then decided the raw aluminum tank looked way cooler then I expected in contrast to the very clean covers. Decisions were made.
All parts then went to paint and powdercoat and whilst waiting on that, the engine had a thorough service at KOBO, a local KTM dealership. With powdercoat and engine back, assembly could start. With the engine in, I began working on the stainless exhaust system. It’s made from elbows, bent tube, and straight tube. Flow/length-wise, I tried to replicate the set LeoVince has for this bike. Back purged, tig-welded, springhooks and bungs added, and Spark mufflers on — exhaust was also done.
As with 90% of the builds I do, there’s a second run to the powdercoater and this time he did the exhaust hangers, speedo bracket, and a couple other small brackets I made during build-up.
It’s a great stress reliever opposed to wanting all powdercoat done in one run, as timeframe-wise, it’s virtually impossible to build the bike completely and then take it apart again for paint and powder as you always tend to forget to make that one little bracket because you changed, added, or removed a part. A second run to the coater solves all that trouble.
Forks were a bit worn and scrubbed, so re-anodised and rebuilt and a set of Pirelli MT60 tires added to the list. Front wheel, calipers, and disks are SuperDuke, so adapters were drawn and CNC’d to make it fit on the adventure forks with some little spacers fresh from the lathe.
Fatbar and risers are supplied by Neken and a Motogadget motoscope mini resides in between the bars and tank, keeping the dash clean. I chose to keep the stock handlebar switches as this bike is ridden daily and needs to be 100% reliable. Not saying aftermarket switches suck, just my personal preference in this case.
This bike will be on display on the BikeShed festival, May 27/28/29 2022 at Tobacco Docks in London, UK.
*This bike is road legal in the Netherlands, was built as a commission and is therefore not for sale. See more of this and other builds by following Outsiders Motorcycles on Instagram: @outsidersmotorcycles.