C100 Spark Plug Cap

C100 Spark Plug Cap - 5Ω Resistor · Waterproof Type

🔥 Spark Plug Cap · Ignition Component · Waterproof Design · EMI Suppression

For Moped, Cub, Dirty Bike & ATV · Fits 139FMB, 147FMD, 147FMF, 150FMG engines

This is a OEM quality spark plug cap with 5Ω internal resistance and a waterproof protective cover. It is a critical component of the engine's ignition system, suitable for Mopeds, Cub series, Dirty Bikes, and ATVs, and fits engines including 139FMB, 147FMD, 147FMF, 150FMG, and similar models.

The spark plug cap connects between the high-tension lead and the spark plug, reliably transmitting high voltage from the ignition coil to the spark plug to ignite the air-fuel mixture. The built-in 5Ω resistor effectively suppresses electromagnetic interference (EMI) generated during ignition, protecting onboard electronic devices such as CDI units, instruments, and charging systems. The waterproof cover prevents water and mud ingress, ensuring reliable ignition in adverse weather conditions. Manufactured from high-quality insulating materials and heat-resistant rubber, this cap offers excellent aging resistance and high-voltage durability. This product is the ideal replacement when the original spark plug cap shows signs of aging, cracking, leakage, or poor contact.

This spark plug cap fits the following engine models:

• Mopeds - Various 50cc-150cc moped models (underbones, scooters, etc.)
• Cub Series - Honda Cub and clone models
• Dirty Bikes - Small off-road motorcycles
• ATVs - Small-engine quad bikes / kids ATVs
• Other vehicles using 139FMB, 147FMD, 147FMF, 150FMG engines

• Hard Starting: Poor high-voltage transmission leads to weak or no spark; engine difficult to start.
• Rough Idle: Unstable ignition energy causes idle fluctuation or hunting.
• Hesitation During Acceleration: Ignition cut-out during hard acceleration; vehicle surges.
• Engine Stalling: Aging cap leaks voltage; engine stalls unexpectedly while riding.
• Wet Weather Issues: Difficulty starting or poor running in rain or after washing; returns to normal when dry.
• Cracked Cap: Visible cracks or damage on rubber or phenolic material.
• Poor Contact: Loose or corroded connection between high-tension lead and spark plug cap.

If you experience these symptoms, inspect the spark plug cap and replace if necessary.

🔧 Installation Tip

1. Before replacing the spark plug cap, remove the spark plug and clean its terminal.
2. Trim approximately 5-10mm from the end of the high-tension lead to expose fresh copper core for good contact.
3. Insert the high-tension lead into the cap terminal and twist to secure; ensure a firm connection.
4. Push the spark plug cap fully onto the spark plug until you hear a "click" indicating proper seating.
5. Verify the waterproof cover fully seals the connection between the cap and high-tension lead.
6. Start the engine and check for voltage leakage (visible spark or noise in damp conditions).
7. If issues persist after replacement, inspect the ignition coil, CDI, and spark plug.

⚠️ Important Notice: This is an OEM quality spark plug cap with 5Ω internal resistance and waterproof cover, suitable for Mopeds, Cubs, Dirty Bikes, ATVs, and vehicles using 139FMB, 147FMD, 147FMF, 150FMG engines.
Resistance Note: The 5Ω resistor is the OEM specification, effectively suppressing electromagnetic interference. Using a non-resistor cap may cause electronic interference, while excessive resistance may affect ignition energy.
Installation Notes: Ensure the high-tension lead core is clean and fully inserted. If ignition problems persist after replacement, inspect the ignition coil, CDI, and spark plug. Images are for reference only. The actual product may vary.