NGK Iridium Spark Plugs DCPR7EIX (97637) for Harley‑Davidson Twin Cam & XL — Set of 4, Fine‑Wire Iridium

NGK 97637 (formerly 6046) DCPR7EIX iridium spark plugs are a four-piece set designed to deliver reliable ignition performance and long service life for Harley‑Davidson Twin Cam and XL engines.

These NGK iridium plugs (new part number 97637, superseding 6046) combine NGK's OEM experience with a fine-wire iridium center electrode to support consistent combustion and extended change intervals. NGK is a global leader in spark plug supply, frequently chosen as original equipment, and this specific plug is built to match the heat range and reach requirements common to many Harley‑Davidson Twin Cam and Sportster (XL) applications. This listing contains four spark plugs—enough for a four-cylinder application or a spare set for two cylinders—sold new and ready for install.

Will these NGK iridium plugs fit my Harley‑Davidson Twin Cam or XL?

Compatibility depends on model year and engine variant, but the DCPR7EIX (NGK 97637, formerly 6046) is widely used in many Twin Cam and select XL (Sportster) engines. Always cross‑reference your motorcycle's factory service manual or parts diagram for plug type, thread reach, and torque specifications before purchase.

• Part number: NGK 97637 (supersedes 6046)
• Type: DCPR7EIX — iridium fine wire center electrode
• Sold as a set of four spark plugs
• Confirm thread reach and gap with OEM specs

How does the iridium construction benefit everyday riding?

Iridium center electrodes have a very fine tip that promotes a more focused spark, which helps with smooth starts, stable idle, and consistent combustion across throttle ranges. That benefit typically results in longer service intervals compared with standard nickel plugs while maintaining reliable ignition under varied riding conditions.

• Fine-wire iridium provides concentrated spark energy
• Improved ignition stability at low and high rpm
• Extended service life versus conventional plugs
• Reduced misfire potential under load

What should I know about installation and maintenance?

Install these plugs using the correct torque and a properly gapped electrode as specified in your motorcycle's manual. Use a torque wrench to avoid over-tightening and check plug condition periodically—electrode wear, deposits, or unusual coloring indicate tuning or mechanical issues that may need attention.

• Set gap to OEM specification before installation
• Tighten to manufacturer torque values to protect threads
• Inspect plugs during routine service intervals
• Replace in matched sets for multi-cylinder engines

Why choose NGK DCPR7EIX instead of a generic plug?

NGK is one of the largest OEM spark plug suppliers worldwide, and their part designs are engineered to meet or exceed factory tolerances. The DCPR7EIX offers a proven heat range and electrode geometry suited to many Harley applications, which helps preserve engine performance and reliability compared with off-brand or incorrectly specified plugs.

• OEM-level manufacturing and quality control
• Accurate heat range and electrode reach for compatibility
• Iridium tip for longer life and consistent spark
• Sold in a convenient four-plug pack

Who is this for? This four-pack of NGK 97637 (6046) DCPR7EIX iridium spark plugs is aimed at Harley‑Davidson owners, mechanics, and enthusiasts who want OEM-grade replacement plugs for Twin Cam and certain XL engines. If you prioritize reliable ignition, longer service intervals, and a direct-fit NGK part number that supersedes 6046, this set is a practical upgrade or routine maintenance purchase. Always verify fitment against your specific model year and engine specifications before ordering.