Sumax S40631 14.4mm Spiral Core Spark Plug Wire Set for Harley-Davidson FXST Softail 2000-2017

The Sumax S40631 is a high-performance 14.4mm spiral-wound spark plug wire set engineered for Harley-Davidson FXST Softail motorcycles from model years 2000 through 2017. Sumax, a division of Taylor Cable Products, is a trusted name in performance ignition technology, offering superior suppression and conductivity over stock OEM wiring.

These oversized 14.4mm plug wires feature a spiral-wound core construction that provides excellent radio frequency interference (RFI) suppression while maintaining strong spark energy delivery to the combustion chamber. The result is a more consistent ignition, improved throttle response, and reliable performance across all riding conditions.

Key Features:

• 14.4mm diameter spiral-core construction for maximum performance and durability
• Superior RFI/EMI suppression to protect modern electronics and instrumentation
• High-temperature silicone jacket resists heat, oil, and abrasion
• Direct-fit replacement — no modifications required for FXST Softail applications
• Covers model years 2000–2017 Harley-Davidson FXST Softail platform
• Manufactured by Sumax / Taylor Cable Products, a trusted ignition wire brand

Upgrade your Softail's ignition system with the Sumax S40631 plug wires for a direct-fit, performance-minded replacement that outlasts and outperforms standard OEM wiring.