Harley SC3 Adventure Dual Sport

Jim Carducci is an engineer with a passion for dual sport motorcycles and the Harley Sportster motor. So he’s put the two together and created the Carducci Dual Sport SC3 Adventure.

Jim bought a 2003 100th Anniversary Sportster “donor” bike—one of the last ‘hard mount’ Sportsters, with a lighter motor than the newer 2004+ model rubber-mounted motors. He then created 2D AutoCAD layouts to lock down the geometry of the frame, motor, suspension, wheels and rider position.

The goal was to get the optimum rake and trail, plus 8+ inches of rear wheel travel and 10+ inches of front wheel travel. The instantaneous force center is now well below the combined CG of the bike + rider—needed for the rear suspension and the traction to work well under acceleration.

With the basics sorted, Jim began a 3D solid-model detailed design. He built a full-scale 3D Styrofoam model of the aluminum 6-gallon gas tank (which was hand formed by Evan Wilcox). He also created a billet aluminum swing arm, triple clamps designed to integrate a Scotts steering damper, and vibration-isolation bar risers. Next came a GPS mount, foot controls, a rear fender sub-frame and rack, a crash bar, a fly screen and a skid plate. And last but not least, a kickstand. Corbin made a seat to Jim’s specs.

The Sportster motor was upgraded with an NRHS 1250cc kit and Andrews N4 cams. The rest of the components are high-spec too: Öhlins forks and rear shocks, configured to handle the Harley’s weight, plus 18” and 21” wheels from Buchanan’s, with Sun rims and a Talon front hub. The exhaust system is from Supertrapp, Biltwell supplied the 1” diameter handlebars, and the foot pegs are from Joker Machine.

“I had a vision of how I could somehow transform a Sportster into a viable dual sport motorcycle,” says Jim. “Others have built variations of the idea, but none suited my eye. And few were truly capable off-road dual sport bikes.”

 “The Sportster motor was the key,” he says. “It produces tractable low-end power and is loaded with torque. Both of which are ideal for dual sporting. Plus, I just love the sound, feel, and look of its V-Twin motor—it has lots of soul!”

Features of the SC3 Adventure Dual Sport Motorcycle
V-Twin Motor

The Sportster® motor is proven reliable, air cooled, narrow and loaded with torque

Frame
Stock Sportster® frame with minor modifications

Suspension
Front: Ohlins 48mm USD forks mounted in strong triple clamps. Integrated Scotts steering damper
Rear: Ohlins twin shocks on extended billet aluminum swingarm

Wheels
140/80-18 rear, 90/90-21 front. A good combination for off-road handling

Lighting
Front headlight is a 55 watt halogen beam (an LED version is also available from Trail Tech®), and LED brake light and blinkers made to handle the vibrations of off-road riding

Fly Screen

The fly screen frame is made of structurally strong sheet aluminum and supports a tinted polycarbonate wind deflector that reduces wind on the body
Controls
Stock Sportster® throttle, speedometer, tachometer, brake, clutch, and wire harness

Rear Rack & Fender Structurally strong for strapping down a tool kit, 2x 1/2 gal fluid cannisters on the sides, and more

Skid Plate

Protects the leading edge and underside of the motor from flying debris and from rolling over large objects like rocks, stumps, et cetera

Crash Bar
Steel welded construction crash bar mounts to the frame and protects the leading edge of the gas tank

Kick Stand
Strong Chromemoly steel tubing with a large foot area for soft off-road surfaces. Adapts to the stock H-D kickstand mount

Stability

Long wheelbase and generous rake and trail make the SC3 Adventure stable at speed and it does well in loose sandy conditions

Riding Position
Foot controls and handlebars are positioned for comfortable dual sport off-road riding standing position. Seat is narrow in the front, wide in the back. Good for standing and longer distance seated riding

Range Hand formed aluminum 6.3 gallon gas tank provides 200+ miles range before hitting reserve. Option for smaller 2.75 gallon aluminum gas tank

SC3 Adventure Basic Specifications
Motor & Frame

'93-'03 Sportster® motor and frame (w/ minor modifications to frame)

Wheelbase
63.5 inch

Steering Rake / Trail
30 degress / 5.6 inch

Triple Clamp Offset
0.71 inch (18mm)

Suspension Travel
+8 inch Rear, +10 inch Front

Seat Height
35.5 inch (neutral), ~33 inch (with rider on bike)

Weight
475 lbs (without gasoline)

Source Carducci Dual Sport  Images by Neil Hanshaw.