C100 Initiative Gear Axle Sheath

C100 Primary Drive Gear Bushing

🔧 Bushing · Sleeve Bearing · Transmission Component

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

This is the C100 Primary Drive Gear Bushing, an important support 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 drive gear bushing (also known as a sleeve bearing or bushing) is installed between the primary drive gear and the crankcase or bearing housing, providing support, positioning, and friction reduction. It ensures smooth rotation of the drive gear on the crankshaft while withstanding radial loads during power transmission. Manufactured from high-quality wear-resistant material, it offers excellent self-lubricating properties and wear resistance. This bushing is the ideal replacement when the original shows signs of wear, excessive clearance, or abnormal noise.

This drive gear bushing 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

• Unusual Noise: Rubbing or rhythmic knocking from the clutch side that changes with engine RPM.
• Drive Gear Play: Noticeable radial clearance or wobble of the drive gear during inspection.
• Uneven Power Delivery: Power feels delayed or jerky during acceleration.
• Jerky Takeoff: Noticeable vibration or jerking when starting from a stop.
• Bushing Wear or Scoring: Visible wear marks or scoring on the bushing inner surface during inspection.
• Metal Particles: Metal powder or debris found in transmission oil during draining.

If you experience these symptoms, inspect the drive gear bushing and drive gear, and replace if necessary.

• OEM Specifications: Manufactured to original dimensions for perfect fitment with drive gear and bearing housing.
• High-Quality Wear-Resistant Material: Made from high-strength wear-resistant alloy or copper-based powder metallurgy with excellent wear resistance.
• Precision Machined: Inner and outer diameters are precision-machined for high dimensional accuracy and smooth surface finish.
• Self-Lubricating Properties: Material offers good self-lubricating characteristics, reducing dependence on oil lubrication.
• Direct Replacement: Directly replaces worn or damaged original bushing without modification.

🔧 Installation Tip

1. Replacing the drive gear bushing requires removing the engine right side cover and drive gear; professional installation is recommended.
2. Thoroughly clean the bearing housing bore and bushing mounting surface to remove oil and debris.
3. Inspect the drive gear shaft journal for wear or scoring; replace if damaged.
4. Use a proper press tool for bushing installation; avoid hammering to prevent deformation or damage.
5. Ensure the bushing is fully seated, flush with the housing face or as per OEM specifications.
6. Apply engine oil to the bushing inner surface for pre-lubrication before installing the drive gear.
7. After installation, manually rotate the crankshaft to check for smooth gear rotation without binding.
8. Fill with appropriate transmission oil and check for abnormal noise after starting the engine.

⚠️ Important Notice: This is a C100 primary drive gear bushing suitable for Mopeds, Cubs, ATVs, and vehicles using 139FMB, 147FMD, 147FMF, 150FMG engines.
Size Confirmation: Different engine displacements may use different bushing dimensions. Before purchase, please confirm your engine model or measure the original bushing inner diameter, outer diameter, and length. Contact customer service if you have any questions.
Installation Notes: Use a proper press tool for installation; avoid hammering. It is recommended to inspect the drive gear shaft journal for wear. Images are for reference only. The actual product may vary.