Upgrade the ignition performance of compatible 1957–1978 Harley-Davidson XL models with Drag Specialties E18-6660SDS spark plugs. Designed for dependable service in motorcycle applications, these spark plugs combine a durable construction with materials selected for thermal stability, electrical insulation, and long-term resistance to corrosion. The black ceramic body and red Drag Specialties logo provide a distinctive appearance while maintaining the performance expected from a quality replacement ignition component.
The insulator is manufactured from 95% pure alumina for strong resistance to heat shock and superior electrical insulation. Its multi-rib design helps eliminate flashover, supporting consistent spark delivery under demanding operating conditions. A nickel-plated housing resists oxidation and corrosion, while multilayer gaskets and a heat-crimping process provide a leak-free, gas-tight fit when properly installed.
A copper-core electrode supports efficient electrical and heat conductivity while helping prevent oxidation and corrosion. This construction promotes reliable ignition and extended spark plug service life. Drag Specialties part number E18-6660SDS is intended for fitment on select 1957–1978 Harley-Davidson XL models; verify the motorcycle’s original equipment specifications, engine configuration, and required heat range before installation. Professional installation and correct tightening torque are recommended for the best results.
Features:
- Fitment: Designed for select 1957–1978 Harley-Davidson XL models
- Brand: Drag Specialties
- Part Number: E18-6660SDS
- Ceramic Insulator: 95% pure alumina construction provides strong heat-shock resistance and superior insulation
- Multi-Rib Design: Helps eliminate flashover for consistent ignition performance
- Housing: Nickel-plated construction resists oxidation and corrosion
- Sealing: Multilayer gaskets and heat-crimping process help create a leak-free, gas-tight fit
- Electrode: Copper-core design provides effective electrical and heat conductivity
- Appearance: Black ceramic body with a bold red Drag Specialties logo and script