Custom 2003 Harley-Davidson Sportster | Doin’ It In The Dirt
2014 Harley-Davidson Off-road MX
Photo: Peter Linney
I bought the donor 2003 Harley-Davidson 883 Sportster, and on the next day I began tearing it apart and started the reverse engineering by measuring the parts that I would keep and design around. Six months later I had a rolling prototype, the SC3 Adventure, which consisted of the Sportster motor and the frame with some minor mods, a custom-designed billet aluminum swingarm, a KTM 525 front end, a small tracker gas tank, 18-inch rear wheel and 21-inch front wheel both with knobby tires, and a hand-modified seat that looked pretty bad. The bike worked well, proving the concept and geometry.
Evan Wilcox hand-formed aluminum 6.3-gallon gas tank
Photo: Peter Linney
I spent the first few months on the CAD system laying out the 2-D architecture side-view before designing and machining any parts. I nailed down the critical geometry: wheelbase, rake, trail, rider position, foot controls, handlebar position, and instantaneous force center related to swingarm length and angle. All are key to the bike performing well on road and off.
Beringer 6-piston radial caliper modified for bigger custom CDS rotor, CDS radial-to-axial adapter bracket
Photo: Peter Linney
Once the architecture was set, I began design engineering the components in 3-D CAD solid modeling. The bike evolved over the next three years, which consisted of refining and adding features like improved suspension, a larger gas tank for longer range, a better seat, a lighter and higher performance exhaust, better brakes, repositioned foot controls, a windscreen, hand guards, and a few other details.
2014 Harley-Davidson Off-road MX
Photo: Peter Linney
My goal was to build the best-performing adventure dual-sport around the H-D Sportster motor and fully document it to be reproducible to spec. I accomplished my goal and have proven the reproducibility by building a second SC3 Adventure through a controlled build. I bought another donor Sportster, ordered all the parts from our drawings and BOM, and then assembled the bike to spec. The entire process took only four months start to finish.
1250cc with NRHS kit
Photo: Peter Linney
Now that both bikes are done, I’m riding them as much as I can, both on the road and in the dirt. On the asphalt, the SC3 Adventure handles the twisties well. It’s a neutral-steering bike that turns effortlessly and at high speeds is inherently stable. Off road in the dirt, the SC3 Adventure is confidence inspiring and loves the open desert roads and sand washes where high speeds are not a problem and the bike is very stable.
2014 Harley-Davidson Off-road MX
Photo: Peter Linney
One of the most asked questions I get is, “Why did you design and build it?” I have a background in engineering disruptive technologies, have been riding Harleys and adventure dual-sports for as long as I can remember, and I wanted to combine the two. I would ask myself and my friends and anyone else that would listen, “Why isn’t there a good American adventure dual-sport?” and, “Will H-D make one?” With my background and experience, I knew I could build a good one based on the hard-mount Sportster chassis model years 1993 to 2003. Since the words “H-D” and “dual-sport” are rarely spoken in the same sentence, once again I was engineering a disruptive product. I knew it would be as controversial a build as it has proven to be. Some love it, some hate it, and it always gets plenty of extreme comments.
Jim Carducci
Photo: Peter Linney
No-Toil billet aluminum, internal vented gas cap
Photo: Peter Linney
2014 Harley-Davidson Off-road MX
Photo: Peter Linney
RELATED | MORE CUSTOM SPORTSTERS
56-tooth chain sprocket
Photo: Peter Linney
Beringer 4-piston caliper and mounting bracket
Photo: Peter Linney
| Specifications | |
|---|---|
| General | |
| Owner | Jim Carducci |
| Shop | Jim Carducci |
| Website | carduccidualsport.com |
| Year/Make/Model | 2014/Harley-Davidson/Off-road MX |
| Fabrication | CDS, Evan Wilcox, Curt Winter of BTRmoto, Corbin seat |
| Machining | LUX Manufacturing for all CNC parts |
| Engine | |
| Year/Type | 2003/H-D Sportster |
| Builder | Jim Carducci |
| Cases | H-D |
| Cylinders | 1250cc with NRHS kit |
| Bore | NRHS 1250cc |
| Pistons | NRHS 1250cc |
| Heads | H-D |
| Rocker Boxes | H-D |
| Cams | Andrews N4 |
| Carburetion | OEM CV carb rejetted |
| Air Cleaner | K&N with ASB carbon-fiber cover |
| Exhaust | RMoto 2-into-1 custom header with Leo Vince muffler with spark arrestor |
| Transmission | |
| Year/Type | 2003/H-D 883 Sportster |
| Gears | H-D 5-speed |
| Clutch | H-D with Mueller lever arm for light clutch pull |
| Primary Drive | RK Racing 530 O-ring chain conversion, 25/56 teeth front/rear sprockets |
| Frame | |
| Year/Type | 2003/powdercoated Sportster |
| Rake/Stretch | 27º/62.5-inch wheelbase |
| Builder | Modified by Jim Carducci |
| Suspension | |
| Front End | Öhlins Off-road MX |
| Length | Length reduced 2.5 in. for 9-in. travel. Stiffer springs. |
| Risers | CDS custom designed CNC-machined billet aluminum includes elastomer vibration dampers, height adjustment, and front/rear adjustment to accommodate rider preference |
| Steering Damper | Integrated Scott’s damper with post mount welded to frame |
| Swingarm | Billet aluminum CNC-machined truss structure extended 4 in.| |
| Rear Shocks | Öhlins twin shocks, 8-in.+ travel at rear axel |
| Wheels, Tires, and Brakes | |
| Front | |
| Builder/Size | Woody’s Wheel Works/21 x 1.85 in. |
| Calipers | Beringer 6-piston radial caliper modified for bigger custom CDS rotor, CDS radial-to-axial adapter bracket |
| Rotors | 1 x 380mm diameter floating custom designed and fabricated by CDS |
| Rear | |
| Builder/Size | Woody’s Wheel Works |
| Caliper | Beringer 4-piston caliper and mounting bracket |
| Rotor | Beringer 291mm diameter floating |
| Pulley | 56-tooth chain sprocket |
| Master Cylinder | Beringer |
| Brake Lines | Melvin custom SST braided |
| Finish/Paint | |
| Paint/Graphics | Designed by Brandon Rike, painted by Ron McRae of OSC| |
| Accessories | |
| Front Fender | Plastic KTM fender |
| Rear Fender | Aluminum fender subframe and utility rack, including support for two 1/2-gallon gas containers |
| Plates | Aluminum skid plate, flyscreen, voltage regulator guard |
| Gas Tank | Evan Wilcox hand-formed aluminum 6.3-gallon |
| Gas Cap | No-Toil billet aluminum, internal vented| |
| Handlebars | Biltwell 1-in. chrome-moly tracker bars |
| Pegs | Pivot Pegz |
| Mirror | DRC 161 off-road mirrors, adjustable height |
| Battery | Shorai lithium-ion |
| Hand Controls | Beringer front brake and clutch levers |
| Foot Controls | CDS custom design billet aluminum shifter, brake, footpegs, supports |
| Shifting | CDS billet aluminum machined linkage and shift lever |
| Kickstand | CDS designed and fabricated chrome-moly tubing with aluminum adapter bracket |
| Headlight | Trail Tech 55-watt halogen Baja flood light |
| Taillight | Acerbis LED |
| Turn Signals | Badlands electronic turn signal module for LED lights |
| Seat | Custom Corbin hand formed to frame and gas tank |
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