C100 Magneto Rotor Comp

C100 6-Pole Rotor Assembly

⚡ Magneto Rotor · Flywheel · Magnet Assembly · Generator Component

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

⚠️ Important Notice: Weak magnetization can cause faulty running, and damaged rotors can cause severe engine damage and noise. Please inspect and replace faulty rotors promptly.

This is the C100 6-Pole Rotor Assembly (also known as magneto flywheel or magnet assembly), a core rotating component of the engine's magneto system. It is suitable for Mopeds, Cub series, and ATVs, and fits engines including 139FMB, 147FMD, 147FMF, 150FMG, and similar models.

The rotor assembly is mounted on the crankshaft end and works with the stator coil. Six permanent magnets are installed inside the rotor. When the engine runs, the rotating rotor generates a changing magnetic field that cuts the stator coil to produce current, powering the ignition and lighting systems. Manufactured with a high-strength alloy steel outer shell and high-quality permanent magnets, this rotor undergoes precision dynamic balancing to ensure smooth operation at high speeds. This assembly is the ideal replacement when the original rotor shows signs of magnet demagnetization, cracks, deformation, or balance issues.

⚠️ Consequences of Rotor Failure

Weak magnetization causes: Low power output, dim lights, weak ignition, hard starting, charging system failure.
Damaged rotor (cracks, deformation, magnet separation) causes: Severe engine noise, stator damage, crankshaft damage, and in severe cases, complete engine failure.

This 6-pole rotor assembly fits the following engine models:

• Mopeds - Various 50cc-150cc moped models (underbones, scooters, etc.)
• Cub Series - Honda Cub and clone models
• ATVs - Small-engine quad bikes / kids ATVs
• Dirt Bikes - Small off-road motorcycles
• Other vehicles using 139FMB, 147FMD, 147FMF, 150FMG engines with 6-pole magneto systems

• Dim/Flickering Lights: Demagnetized magnets reduce power output; headlight brightness drops significantly.
• Charging System Failure: Battery does not charge; electric start is weak.
• Hard Starting/No Start: Weak ignition energy; spark plug shows weak or no spark.
• Engine Noise: Loose rotor or separated magnets cause clicking or metallic grinding sounds.
• Severe Vibration: Rotor imbalance or deformation causes engine vibration during operation.
• Stator Damage (Scoring): Deformed rotor or failed bearings cause rotor-stator contact, producing metal powder.
• Weak Magnetic Force: Reduced attraction when testing with a ferrous tool.

If you experience these symptoms, inspect the rotor assembly and replace if necessary. Delayed repair may lead to more severe engine damage.

• OEM Specifications: Manufactured to original dimensions and magnet configuration for perfect fitment.
• High-Performance Permanent Magnets: Strong magnetic force with low demagnetization rate for stable power output.
• High-Strength Outer Shell: Alloy steel construction for durability and impact resistance.
• Precision Dynamic Balancing: Factory-balanced for smooth operation at high RPM.
• 6-Pole Design: Provides ample power for lighting and charging needs.
• Direct Replacement: Directly replaces demagnetized or damaged original rotor without modification.

🔧 Installation Tip

1. Replacing the rotor assembly requires removing the left engine cover; professional installation is recommended.
2. Clean the crankshaft taper and rotor bore thoroughly to remove oil and debris.
3. Inspect the crankshaft woodruff key for wear; replace if necessary.
4. Align the keyway during installation; use a proper puller tool to install the rotor, never hammer.
5. Tighten the rotor retaining nut to the specified torque for secure fastening.
6. After installation, manually rotate the crankshaft to check for binding or unusual noise.
7. Start the engine and verify proper charging voltage and lighting brightness.
8. Listen for abnormal noise during operation to ensure smooth running.

⚠️ Important Notice: This is a C100 6-pole rotor assembly, suitable for Mopeds, Cubs, ATVs, and vehicles using 139FMB, 147FMD, 147FMF, 150FMG engines with 6-pole magneto systems.
Safety Warning: Weak magnetization can cause faulty running, and damaged rotors can cause severe engine damage and noise. Inspect rotor condition regularly and replace immediately if any abnormality is found.
Specification Confirmation: Please verify your original rotor is a 6-pole type before purchase. Use proper tools during installation; never hammer. Images are for reference only. The actual product may vary.