Harley-Davidson X440 Spark Plug (REK6YCA) – Genuine OEM Type – HDH31916ABW801S / 31916ABW801S (Mavrick 440)

A weak or worn spark plug is one of the most common reasons for hard starting, rough idle, misfires, poor pickup, and reduced fuel economy—especially in stop-go Indian traffic. This REK6YCA Spark Plug is the correct OEM-type replacement used on the Hero Mavrick 440 platform and is engineered for consistent ignition under high heat and load.

This listing covers the spark plug referenced as 31916ABW801S on Hero’s official parts store (marked applicable for MAVRICK 440), and it is also commonly circulated in the market with the Harley/Hero prefix format as HDH31916ABW801S for the 440 platform. 

If you’re servicing a 440 platform motorcycle, replacing the spark plug at the right interval helps restore smooth cold starts, cleaner combustion, and crisp throttle response—without risking the “wrong plug” issues that happen with generic matches.

Why buy from Under The Hood: We’re building India’s most accurate Harley 440X / 440 platform spares catalogue, ship safely packed, and can help confirm fitment if you share your VIN/RC details on WhatsApp/chat.

Key Features 

• Part / Type: Spark Plug REK6YCA (Genuine OEM-type)

• Part Number (Hero): 31916ABW801S 

• Market Reference Code: HDH31916ABW801S (commonly listed by independent parts sellers) 

• Primary Use: Reliable ignition, smoother starting, stable idle, cleaner combustion 

• OEM quality focus: Designed to handle high temperature/pressure for long-lasting performance 

• Helps reduce: Misfire feel, hesitation, weak pickup (when plug is worn/aged)

• Best practice: Replace with correct code instead of “similar-looking” plugs (prevents heat-range mismatch issues)

• Pan-India shipping: Secure packing to protect ceramic insulator + electrode during transit

Compatibility Table

What’s in the Box

• 1 × Spark Plug REK6YCA (1 piece) 
  Not included: plug cap, ignition coil, tools, or any “service kit” items.

Installation & Maintenance Notes

• Install on a cold engine to protect threads and ensure correct seating.

• Ensure the plug area is clean before removal to avoid debris entering the cylinder.

• If your plug uses a sealing washer, ensure it seats properly; do not cross-thread.

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FAQs 

Q1. Is this spark plug genuine / OEM type?
Yes. This is listed as Harley-Davidson Genuine Spark Plug – REK6YCA (31916ABW801S) 

Q2. Will it fit Hero Mavrick 440?
Yes. The Hero listing explicitly includes MAVRICK 440 under “Model Applicable.” 

Q3. Will it fit Harley-Davidson X440 / 440X?
HDH31916ABW801S is a confirmed fitment for fit Harley-Davidson X440 / 440X.

Q4. What symptoms suggest my spark plug needs replacement?
Hard starting, unstable idle, misfire/jerk under load, weak pickup, or reduced mileage—especially if the plug is old or fouled.

Q5. Can I use a “similar” spark plug from a local shop?
Not recommended. Heat range and reach differences can cause performance issues. Using the correct code helps avoid misfires and long-term engine stress.

Q6. Is professional installation required?
If you’re comfortable with basic maintenance, it’s straightforward—but avoid cross-threading. If unsure, use a trained mechanic.