C100 Primary Driven Gear 69T

C100 Primary Driven Gear

⚙️ Primary Drive Gear · Clutch Gear · Transmission Component

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

This is the C100 Primary Driven Gear, a critical component of the engine's primary drive system. It is suitable for Mopeds, Cub series, and ATVs, and fits engines including 139FMB, 147FMD, 147FMF, 150FMG, and similar models.

The primary driven gear (also known as clutch gear or primary driven sprocket) is mounted on the clutch assembly and meshes with the primary drive gear on the crankshaft. It transmits power from the crankshaft to the clutch, which then transfers power to the transmission. Manufactured from high-quality alloy steel with precision-machined teeth and heat treatment, it offers excellent wear resistance, impact strength, and transmission accuracy. It is the ideal replacement when the original gear shows wear, broken teeth, or abnormal noise.

This primary driven gear 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

• Transmission Noise: Rhythmic gear engagement noise or knocking from the clutch side that changes with engine RPM.
• Jerky Takeoff: Noticeable vibration or jerking when starting from a stop, indicating uneven power transmission.
• Power Loss: Reduced power transfer efficiency, especially noticeable during hard acceleration.
• Worn or Broken Teeth: Inspection reveals severe wear, pitting, or chipped/broken teeth on the gear.
• Clutch Slipping Sensation: Severe gear wear may create a sensation similar to clutch slippage.
• Metal Particles: Metal powder or debris found in transmission oil during draining.

If you experience these symptoms, inspect the primary driven gear and matching drive gear, and replace if necessary.

• OEM Specifications: Manufactured to original tooth profile, count, and dimensions for perfect meshing with the drive gear.
• High-Quality Alloy Steel: Made from high-strength alloy steel with excellent toughness and fatigue resistance.
• Precision-Machined Teeth: Precision hobbing and grinding ensure smooth engagement and high transmission efficiency.
• Carburizing & Hardening: Professional heat treatment provides high surface hardness and superior wear resistance for long service life.
• Direct Replacement: Directly replaces worn or damaged original primary driven gear without modification.

🔧 Installation Tip

1. Replacing the primary driven gear requires removing the engine right side cover and clutch assembly; professional installation is recommended.
2. Thoroughly clean the gear mounting surface and clutch assembly to remove oil and debris before installation.
3. It is recommended to inspect and replace the matching primary drive gear (crankshaft gear) simultaneously to ensure proper gear meshing.
4. Pay attention to gear orientation during installation and ensure proper seating with the clutch drum.
5. Tighten the clutch fixing nut to the specified torque to ensure the gear assembly is securely fastened.
6. After installation, manually rotate the crankshaft to check for smooth gear engagement without binding.
7. Fill with appropriate transmission oil, start the engine, and check for abnormal noise to confirm proper operation.

⚠️ Important Notice: This is a C100 primary driven gear suitable for Mopeds, Cubs, ATVs, and vehicles using 139FMB, 147FMD, 147FMF, 150FMG engines. Different engine displacements may have different primary reduction ratios and tooth counts. Please verify your original gear tooth count or specific engine model before purchase. It is recommended to replace the matching primary drive gear simultaneously for optimal meshing condition. Images are for reference only. The actual product may vary.