| Attribute | Specification |
|---|---|
| Production Years | 1999–2005 |
| Engine Type | Twin Cam 88 (V-Twin) |
| Engine Oil | SAE 20W50 (2.4 L) |
| Spark Plugs | H-D 6R12 |
| Battery | 65989-97C |
| Front Tire | 100/90-19 57H |
| Rear Tire (99-01) | 130/90B16 67H |
| Rear Tire (02-05) | 150/80B16 71H |
Engineering Highlight: The FXDX remains a cult favorite among performance enthusiasts because it was the first Dyna to feature fully adjustable cartridge-style front forks and adjustable rear shocks from the factory. This engineering decision transformed the traditional cruiser geometry into a machine capable of significant lean angles and high-speed stability, bridging the gap between Milwaukee iron and sporting performance.
Technical Review: The Rider’s Harley
At MotoSpecsLab, we categorize the FXDX as the “Apex Predator” of the Twin Cam 88 era. While other Dynas focused on chrome and aesthetics, the Super Glide Sport was stripped down for function. It featured a triple-disc braking system (dual front rotors) which provided stopping power that far exceeded its contemporaries in the H-D lineup.
The heart of the machine is the Twin Cam 88 engine, rubber-mounted to the frame to isolate vibration while maintaining the visceral feel of a large-displacement V-twin. The blacked-out engine treatment and staggered shorty dual exhausts gave it a distinct, aggressive profile that remains timeless.
Maintenance Guide & Essentials
Lubrication System
For optimal thermal stability, the FXDX requires SAE 20W50 oil. The oil capacity is 2.4 Liters. Given the air-cooled nature of the Twin Cam engine, we recommend high-quality synthetic fluids to protect the top end during high-temperature operation.
Tires and Chassis
The FXDX underwent a significant change in 2002. Models from 1999–2001 utilize a 130/90B16 rear tire, while the 2002–2005 models were upgraded to a wider 150/80B16 rear tire for improved footprint and grip.
Tire Pressures:
- Front: 2.1 bar (30 psi)
- Rear (Solo): 2.5 bar (36 psi)
- Rear (Two-up): 2.8 bar (40 psi)
Electrical & Ignition
The ignition system relies on H-D 6R12 spark plugs. For reliable starting, especially given the high-compression nature of the V-twin, ensure the 65989-97C battery is maintained with a tender during off-seasons. The FXDX’s charging system is robust, but aging stators are a known point of inspection for high-mileage units.
MotoSpecsLab Verdict
The FXDX is a rare breed of motorcycle that offers the soul of a Harley-Davidson with the handling characteristics of a standard bike. For the modern collector or rider, it represents the pinnacle of the Dyna’s mechanical evolution before the move to the 96ci engine and the eventual discontinuation of the Dyna platform.