Custom 2003 Harley-Davidson Sportster | Doin’ It In The Dirt | Hot Bike

Custom 2003 Harley-Davidson Sportster | Doin’ It In The Dirt

A super-engineered SC3 Adventure

2014 Harley-Davidson Off-road MX

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

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

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

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

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

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

Jim Carducci

Photo: Peter Linney

No-Toil billet aluminum, internal vented gas cap

No-Toil billet aluminum, internal vented gas cap

Photo: Peter Linney

2014 Harley-Davidson Off-road MX

2014 Harley-Davidson Off-road MX

Photo: Peter Linney

56-tooth chain sprocket

56-tooth chain sprocket

Photo: Peter Linney

Beringer 4-piston caliper and mounting bracket

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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