Royal Enfield Suppressor Cap Kit – Classic 350 UCE, Bullet 350/500, Thunderbird 350/500 – KAC00020 / KAC00020/A (Genuine RE Ignition Cap)

The Royal Enfield Suppressor Cap Kit KAC00020 / KAC00020/A is the genuine OEM ignition cap that connects your ignition coil to the spark plug on UCE 350/500 models. This small part plays a big role: it carries high voltage from the coil, insulates it from engine heat and vibration, and suppresses electrical noise so your bike starts easily and runs smooth even in harsh Indian riding conditions.

Multiple trusted dealer listings confirm that KAC00020/A is the factory-specified suppressor cap for Classic 350 UCE, Bullet 350/500 and Thunderbird 350/500 models. Unlike cheap aftermarket caps that crack, arc or lose grip over time, this kit is built to Royal Enfield standards with proper sealing, snug spark plug fit and reliable resistance value for clean combustion and consistent power delivery.

If your bike shows symptoms like hard starting, random misfires, poor idling, or intermittent power loss, a worn suppressor cap is a common culprit. Replacing it with a genuine KAC00020/A kit is a simple, low-cost fix that can dramatically improve reliability—especially on long rides and touring builds.

At Under The Hood, we ship only 100% genuine, sealed Royal Enfield parts, clearly labeled with OE part number so you can match it to your existing cap and reduce return headaches.

Key Features 

• Genuine Royal Enfield OE Part – Original Suppressor Cap Kit KAC00020 / KAC00020/A, as listed in RE part lines and dealer catalogs.

• Correct Fit for UCE Singles – Designed for Royal Enfield Classic 350 UCE, Bullet 350/500, Thunderbird 350/500 (see detailed compatibility below).

• Improved Ignition Reliability – Ensures a strong, stable connection between ignition coil and spark plug to reduce misfires and starting issues.

• Built-in Noise Suppression – Internal resistor helps cut down electrical interference for smoother engine operation and less EMI.

• Heat & Vibration Resistant Construction – High-quality insulating body designed to survive engine heat, rain, dust and bad roads.

• Plug-and-Play Replacement – Direct swap for the stock suppressor cap on compatible UCE models; no wiring cuts or modifications needed.

• Ideal Preventive Maintenance – Recommended whenever you change plug leads, chase intermittent misfire, or restore an older Bullet/Classic/Thunderbird.

• 100% Genuine, Fresh Stock – Supplied in original Royal Enfield packaging with part number; no loose or unpacked local copies.

Compatibility Table

CHECK PART NUMBER BEFORE PURCHASE 

(THIS IS A KIT AND HAS ADAPTOR FOR BOTH SIDES)

Variants

• Single Standard Variant:

  • Part Number: KAC00020 / KAC00020/A

  • Type: Suppressor Cap Kit (Spark Plug Cap)

FAQs 

Q1. What exactly does the Suppressor Cap Kit KAC00020/A do?
A. It is the spark plug cap that connects the ignition coil to the spark plug. It insulates the high voltage, locks onto the plug terminal, and has a resistor to suppress electrical noise. A bad cap can cause misfires, poor starting and rough running.

Q2. Will this fit my Classic 350 Reborn / Meteor 350 / Hunter 350?
A. No. This part is confirmed for UCE-era Classic 350, Bullet 350/500 and Thunderbird 350/500 only. J-Series bikes (Classic Reborn, Hunter, Meteor, new Bullet 350) use a different ignition setup and require different part numbers.

Q3. Does the kit include the HT lead (wire) or only the cap?
A. This listing is for the Suppressor Cap Kit only, as supplied by Royal Enfield. On most UCE bikes the existing HT lead can be reused if in good condition; if your cable is cracked or hardened, we recommend changing that as well.

Q4. How do I confirm fitment before ordering?
A. Match your existing cap’s part number (should be KAC00020 or KAC00020/A) and ensure your bike is one of the UCE models listed in our compatibility table. You can also confirm with your local RE dealer using your VIN/chassis number.

Q5. Is this better than aftermarket plug caps?
A. Yes. Genuine RE caps like KAC00020/A are built to OE spec for correct resistance, grip and sealing. Aftermarket copies often crack early or lose contact, which brings back starting and misfire issues.