1. Introduction
Thank you for choosing the YOWSOM Motorcycle Starter Motor. This manual provides essential information for the safe and effective installation, operation, and maintenance of your new starter motor. Please read this manual thoroughly before installation and keep it for future reference. This product is designed as a direct replacement for the original equipment manufacturer (OEM) part 4ST-H1800-00.
2. Product Overview
The YOWSOM Starter Motor is a critical component in your motorcycle's ignition system, responsible for converting electrical energy from the battery into mechanical energy to crank the engine. This starter motor features a durable construction, is designed to be waterproof, and utilizes a carbon brush type for reliable performance.
Figure 1: Side view of the YOWSOM Motorcycle Starter Motor. This image shows the main body of the starter motor, including the motor housing and the drive gear end.
Figure 2: Angled view of the starter motor, highlighting the drive gear and mounting points. A protective cap is also visible.
Figure 3: Rear view of the starter motor, showing the end cap and the two mounting bolts.
Figure 4: End view of the starter motor, clearly showing the electrical terminal for connection to the motorcycle's wiring harness.
Figure 5: Another side view of the starter motor, providing a clear perspective of the electrical connection point and the overall compact design.
3. Compatibility
This YOWSOM Starter Motor is compatible with the following motorcycle models:
- Yamaha TTR90
- Yamaha CRYPTON T105E
It is designed to replace OEM part number 4ST-H1800-00. Please verify your motorcycle's model and existing starter motor part number before installation to ensure proper fitment.
4. Safety Information
Always prioritize safety when working on your motorcycle. Failure to follow safety precautions can result in serious injury or damage to the vehicle.
- Disconnect the battery's negative terminal before beginning any electrical work to prevent accidental short circuits or electrical shock.
- Wear appropriate personal protective equipment (PPE), including safety glasses and gloves.
- Ensure the motorcycle is stable and securely supported on a stand before working underneath it.
- Allow the engine to cool completely before working on any engine components.
- If you are unsure about any step of the installation process, consult a qualified motorcycle mechanic.
5. Installation
This starter motor is designed for simple, direct replacement of the original part. While the installation process is generally straightforward, it requires basic mechanical knowledge and tools. If you are not confident in performing this task, it is recommended to seek professional assistance.
General Installation Steps:
- Prepare the Motorcycle: Ensure the motorcycle is turned off and the ignition key is removed. Disconnect the negative (-) terminal of the battery.
- Locate the Starter Motor: Identify the location of the existing starter motor on your Yamaha TTR90 or CRYPTON T105E. Refer to your motorcycle's service manual for exact location and removal procedures.
- Disconnect Wiring: Carefully disconnect the electrical wiring from the old starter motor. Note the position of each wire for correct reinstallation.
- Remove Mounting Bolts: Loosen and remove the bolts securing the old starter motor to the engine casing.
- Remove Old Starter Motor: Gently pull the old starter motor out from its housing. Be mindful of any gaskets or O-rings.
- Inspect and Clean: Inspect the mounting area for any debris or corrosion. Clean as necessary.
- Install New Starter Motor: Insert the new YOWSOM starter motor into the housing. Ensure it seats correctly.
- Secure Mounting Bolts: Reinstall the mounting bolts and tighten them to the manufacturer's specified torque (refer to your motorcycle's service manual).
- Reconnect Wiring: Reconnect the electrical wiring to the new starter motor, ensuring all connections are secure and correctly positioned.
- Reconnect Battery: Reconnect the negative (-) terminal of the battery.
- Test Functionality: Attempt to start the motorcycle to verify the new starter motor is functioning correctly. Listen for unusual noises.
6. Operation
The starter motor's operation is integrated with your motorcycle's ignition system. When you press the start button, electrical current flows from the battery to the starter motor. The starter motor then engages a small gear (bendix gear) with the engine's flywheel, rotating the crankshaft to initiate the combustion process. Once the engine starts, the starter motor disengages automatically.
7. Maintenance
While starter motors are generally low-maintenance components, periodic checks can help ensure longevity and reliable performance:
- Battery Condition: Ensure your motorcycle battery is in good condition and fully charged. A weak battery can strain the starter motor.
- Electrical Connections: Periodically check the starter motor's electrical connections for corrosion or looseness. Clean and tighten as necessary.
- Mounting Security: Ensure the starter motor remains securely mounted to the engine.
8. Troubleshooting
If you experience issues with your starter motor, consider the following common problems and solutions:
| Symptom | Possible Cause | Solution |
|---|---|---|
| Starter motor does not turn or clicks once | Dead or weak battery, loose battery terminals, faulty starter solenoid, faulty ignition switch | Check battery charge and terminals. Test starter solenoid. Inspect ignition switch. |
| Starter motor cranks slowly | Low battery charge, corroded battery cables, high resistance in circuit | Charge or replace battery. Clean battery cables and terminals. Check for proper grounding. |
| Starter motor spins but engine does not crank | Faulty bendix gear (starter drive), damaged flywheel teeth | Inspect starter drive and flywheel. Replacement of starter motor may be necessary. |
| Grinding noise during starting | Misaligned starter motor, damaged flywheel teeth, worn starter gear | Check starter motor alignment and mounting. Inspect flywheel and starter gear for damage. |
If these troubleshooting steps do not resolve the issue, it is recommended to consult a professional motorcycle mechanic.
9. Specifications
| Feature | Detail |
|---|---|
| Brand | YOWSOM |
| OEM Part Number | 4ST-H1800-00 |
| Internal Model Number | YXSM789 |
| Compatibility | Yamaha TTR90, CRYPTON T105E |
| Brush Type | Carbon |
| Waterproof | Yes |
| Durability | Durable construction |
| Package Includes | 1 set starter motor |
| Package Dimensions | 1.18 x 0.79 x 0.39 inches |
| Item Weight | 1.34 pounds |
| Assembly Required | No (direct replacement) |
10. Warranty and Support
YOWSOM is committed to customer satisfaction. If this starter motor does not meet your expectations or if you encounter any issues, please contact the seller or manufacturer directly for assistance. We are dedicated to addressing all your concerns promptly.
