Heavy-Duty Design and Unmatched Durability

The HI-4N module features a rugged aluminum housing designed to withstand the extreme heat and vibration found inside the engine’s nose cone. Unlike other modules that use plastic or thin metal, the HI-4N is built to last. The internal electronics are fully potted to protect against moisture and mechanical shock, ensuring that your ignition timing stays rock-solid through thousands of miles of hard riding.

Total Tuning Control: Selectable Advance Curves

Every engine has unique timing requirements based on its cam profile, compression ratio, and fuel quality. The HI-4N features easy-to-use rotary switches that allow you to select between multiple advance curves. You can fine-tune the timing to prevent engine knock (detonation) while maximizing torque and top-end power. Additionally, the module features a separate curve for rear cylinder timing, allowing for precise offset adjustments to keep your engine running cooler and smoother.

Optimized Single-Fire Performance

This kit includes a high-output single-fire coil, which is a major upgrade over the stock “dual-fire” setup. In a single-fire system, each cylinder receives a spark only on its compression stroke, eliminating the “wasted spark” on the exhaust stroke. This results in reduced engine vibration, easier starting, and a more stable idle. The matched coil ensures that the HI-4N module can deliver a hotter, more consistent spark across the entire RPM range.

Advanced Features: Rev Limiter & Start Modes

The HI-4N is packed with professional-grade features, including a built-in adjustable rev limiter that can be set in 100-RPM increments to protect your valvetrain. It also features a specialized Kick-Start mode that provides a spark on the very first compression stroke, making it much easier to fire up kick-only custom builds. For electric-start bikes, the standard mode delays the spark for two revolutions to protect the starter motor from violent kick-back.

Fitment and Compatibility (1984–1999)

This kit (Part # 550-0502) is designed for “nose cone” ignition applications, including:

• Harley Big Twin (1984–1999): Evolution (Evo) engines (Softail, Dyna, Touring).
• Harley Sportster (1986–2003): All 883 and 1200 Evolution Sportster models.
• S&S Engines: Direct fit for S&S V-Series engines and other aftermarket Evo-style builds.