C100 Main Shaft Assy - Automatic

Brand: Mortch Motor
Product Code: MIC100-6037

Product Viewed: 191

Availability: Pre-Order

Weight: 0.28kg

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C100 Main Shaft Assembly - Automatic Clutch Type

⚙️ Main Shaft · Automatic Clutch Shaft · Transmission Component

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

📋 Product Overview

This is the C100 Main Shaft Assembly - Automatic Clutch Type, a core power transmission component of the engine's transmission. It is suitable for Mopeds, Cub series, and ATVs, and fits engines including 139FMB, 147FMD, 147FMF, 150FMG, and similar models.

The main shaft assembly (automatic clutch type) is installed in the transmission, meshing with the countershaft gears to distribute power from the clutch to each gear. Manufactured from high-strength alloy steel with precision-machined and heat-treated gears, it offers excellent wear resistance and fatigue strength. The automatic clutch type main shaft integrates centrifugal clutch components for automatic clutch operation. This assembly is the ideal replacement when the original main shaft shows signs of gear wear, bearing damage, bending, or abnormal noise.

✨ Key Functions: Transmits power to transmission · Supports gear sets · Automatic clutch control · Precision gear meshing · Smooth shifting

📐 Specifications

Product Name

Main Shaft Assembly - Auto Clutch Type

Engine Application

139FMB / 147FMD / 147FMF / 150FMG

Material

High-Strength Alloy Steel

Type

Automatic Clutch Main Shaft

Heat Treatment

Carburizing · Surface Hardening

Gears

3-Speed / 4-Speed (varies)

🔧 Main Shaft Specifications

⚠️ Important: Different engine displacements may use different main shaft configurations and gear counts. Please select the correct specification based on your engine model!

70cc / 90cc Specification

Displacement: 70cc / 90cc

Gear Count: 3-Speed / 4-Speed

Shaft Length: Standard

Engine Models: 139FMB, 147FMD

110cc / 125cc Specification

Displacement: 110cc / 125cc

Gear Count: 4-Speed

Shaft Length: Standard

Engine Models: 147FMF, 150FMG

📌 Size Selection Guide: Different displacement engines may use different main shaft configurations and gear counts. To ensure accurate fitment, it is recommended to verify your original main shaft specifications or contact customer service.

🔧 Compatible Engine Models

This main shaft assembly fits the following engine models:

139FMB

147FMD

147FMF

150FMG

Engine Reference Information:

139FMB: 1P39FMB / 1P39QMB · 50cc-125cc universal engine
147FMD: 1P47FMD · 70cc-110cc engine
147FMF: 1P47FMF · 90cc-110cc engine
150FMG: 1P50FMG · 125cc-150cc engine

🛵 Compatible Vehicles

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 automatic clutch transmission

📌 Compatibility Note: This main shaft assembly is suitable for the automatic clutch version of the engine models listed above. Please verify your transmission type is automatic clutch and confirm the gear count before purchase.

⚙️ Importance of Main Shaft Assembly

🔄 Power Distribution

Transmits power from the clutch to all gear sets, serving as the core transmission shaft.

⚙️ Gear Support

Supports all gear sets, ensuring proper meshing and smooth power transfer.

🔧 Automatic Clutch Integration

Integrates centrifugal clutch components for automatic clutch operation.

🛡️ Shift Quality

Gear precision directly affects shifting smoothness and riding comfort.

⚠️ Main Shaft Failure Symptoms: Transmission noise (gear whine or knocking), difficult shifting, gear jumping, uneven power delivery, automatic clutch slipping or failure to disengage. If these occur, inspect and replace the main shaft assembly and matching gears.

⚠️ Common Failure Symptoms

Transmission Noise: Rhythmic gear noise or knocking from the transmission area that changes with engine RPM.
Difficult Shifting: Stiff or rough shifting, difficulty engaging gears.
Gear Jumping: Unexpected disengagement from gear during acceleration or deceleration.
Uneven Power Delivery: Delayed or jerky power response during acceleration.
Automatic Clutch Issues: Slipping or juddering during takeoff, or failure to disengage causing stalling.
Gear Wear or Damage: Inspection reveals worn, pitted, or chipped gear teeth, or damaged bearings.

If you experience these symptoms, inspect the main shaft assembly and countershaft assembly, and replace if necessary.

✨ Product Features

OEM Specifications: Manufactured to original gear parameters and dimensions for perfect fitment.
High-Strength Alloy Steel: Made from premium alloy steel with excellent strength and toughness.
Precision-Machined Gears: Precision hobbing and grinding for smooth engagement and low noise.
Carburizing & Hardening: Gear teeth undergo carburizing and hardening for high surface hardness and superior wear resistance.
Automatic Clutch Integration: Designed for automatic clutch transmissions.
Direct Replacement: Directly replaces worn or damaged original main shaft assembly without modification.

🔧 Installation Tip

1. Replacing the main shaft assembly requires disassembling the engine transmission; professional installation is recommended.
2. Thoroughly clean the transmission case and inspect bearing bores for wear before installation.
3. Inspect countershaft gears for wear; it is recommended to replace the countershaft assembly simultaneously.
4. Use proper tools to install bearings; avoid hammering to prevent damage.
5. Pay attention to gear orientation during installation; ensure shift fork grooves are properly aligned.
6. Tighten bearing retaining bolts and shift mechanism screws to the specified torque.
7. After installation, manually rotate the main shaft to check smooth gear engagement through all gears.
8. Add appropriate transmission oil, start the engine, and verify normal operation in all gears.

⚠️ Important Notice: This is a C100 main shaft assembly - automatic clutch type, suitable for Mopeds, Cubs, ATVs, and vehicles using 139FMB, 147FMD, 147FMF, 150FMG engines with automatic clutch transmissions.
Specification Confirmation: Different engine displacements may use different main shaft configurations and gear counts. Before purchase, please verify your transmission type is automatic clutch and confirm the gear count. Contact customer service if you have any questions.
Installation Notes: Pay attention to gear orientation and proper bearing installation. It is recommended to inspect the countershaft assembly simultaneously. Images are for reference only. The actual product may vary.

🔧 Compatibility Notice

Please verify that this part fits your specific vehicle model and year. Many vehicles share similar names but use different components depending on year or market region.
We strongly recommend cross-checking with your vehicle's owner's manual or contacting us for confirmation before placing your order.

📄 Product Disclaimer

Product images, measurements, and descriptions are for reference only. Slight variations in color or appearance may occur due to manufacturing batches or photography lighting—functional specifications remain identical to the ordered part.
Professional installation is mandatory. Mortch Motor assumes no liability for damages, injuries, or losses resulting from improper installation, misuse, unauthorized modification, or abnormal operation.

💰 Import Duties & Taxes

All listed prices EXCLUDE shipping costs, import duties, taxes, and customs clearance fees. These charges (if applicable) are determined and collected by your local customs authority and are solely the buyer's responsibility.
In case of return due to unpaid duties/taxes or refusal to clear customs, the buyer shall bear the original shipping cost, return shipping fees, and any associated administrative charges deducted from the refund.

📌 Order Confirmation: By completing your purchase, you acknowledge that you have read, understood, and agreed to all terms above. For any questions, please contact our support team prior to ordering.