STONEDER Dual Stage Foam Air Filter User Manual

1. Introduction

1.1 Foreword

This manual provides clear and detailed instructions for installation, usage, maintenance, and safety precautions to help you operate the air filter correctly, ensure optimal performance, and guarantee your riding safety. Please read all contents thoroughly before installation and use. For any questions, contact your after-sales service team.

This air filter has undergone rigorous quality testing and complies with national motorcycle accessory safety standards and relevant industry regulations. Misuse, incorrect installation, or failure to maintain according to instructions may result in accessory damage, motorcycle malfunction, or even safety incidents. Any resulting losses shall be borne solely by the user.

1.2 Product Overview

1.2.1 Product Purpose

This air filter is an OEM-specific replacement part for Yamaha ATVs, designed to replace aged, damaged, or worn air filtration components. It restores normal engine functionality by ensuring clean air intake, thereby ensuring riding safety, stability, and optimal engine performance.

1.2.2 Product Features

• Premium Materials: Crafted from high-quality dual-stage foam, offering excellent filtration, durability, wear resistance, and heat resistance for extended service life.
• Superior Compatibility: Manufactured to exact OEM dimensions and standards, ensuring precise fitment for designated Yamaha ATV models. Direct installation without modification, achieving seamless integration with the ATV's air box.
• Stable Performance: Rigorous testing ensures performance meets OEM standards, effectively restoring optimal air filtration for stable, reliable engine operation.
• Safe and Reliable: Complies with national safety standards for motorcycle parts, eliminating safety hazards and effectively enhancing engine longevity by preventing harmful debris from entering.

Image 1: STONEDER Dual Stage Foam Air Filter (Yellow foam with black base ring)

2. Setup and Installation

2.1 Installation Preparation

2.1.1 Installation Environment Requirements

• Select a level, dry, well-ventilated location free of flammable or explosive materials for installation. Avoid operating in damp, muddy, oily, or direct sunlight environments.
• The installation site must provide sufficient working space for component removal and installation. Keep unauthorized personnel away to prevent accidents.

2.1.2 Safety Preparations

• Before installation, wear protective gloves to prevent cuts from sharp edges, contamination from oil, or burns from hot components (e.g., ensure the engine is cool when working near engine-related parts).
• When working with small components or in tight spaces, wear safety goggles to prevent small parts or debris from entering the eyes.
• Before installation, confirm the ATV engine is turned off and the ignition key removed to disconnect power. Ensure the ATV is stable and secured to prevent tipping during installation.

2.1.3 Accessory Inspection

• Open the product packaging and inspect the air filter for any visible damage, including deformation, cracks, scratches, or tears in the foam. Ensure the surfaces are free of oil stains or dirt.
• Verify that the model and specifications of the air filter match your ATV model and correspond to the information on the product packaging.
• Verify that all accompanying accessories (e.g., sealing gaskets, if included) are present and undamaged.
• If you discover any damaged parts, mismatched models, or missing accessories, immediately cease use. Contact your dealer for replacement or reissuance. Do not force installation.

2.2 Installation Steps

Important Notice: Before installation, ensure the ATV engine is turned off, the power is disconnected, and the vehicle is securely supported. Handle all components with care during installation to avoid collisions, damage to parts, or ATV components. Strictly follow the steps below without skipping any procedures. If you lack installation experience, we recommend visiting a professional ATV repair shop for installation by a qualified technician.

2.2.1 Removing Old Components

1. Based on your ATV model and the old air filter's mounting location (typically within the air box), first wipe the old air filter and surrounding areas with a cloth to remove surface grease, dust, and debris, facilitating identification of removal points.
2. Using appropriate tools (e.g., screwdriver for air box clamps), slowly remove any fasteners securing the old air filter. During disassembly, note the position and quantity of each fastener to prevent loss or misplacement. (Taking photos for reference is recommended).
3. If fasteners are seized or rusted during removal, spray a small amount of rust remover on the connection point. Wait briefly before attempting removal. Never force the parts, as this may damage bolts, threads, or ATV components.
4. Gently remove the old air filter. Note its installation orientation, angle, and connection relationships with surrounding components to serve as a reference for installing the new part. After removal, clean the air box mounting surface and connection points with a cleaner to remove residual oil, debris, and dirt, ensuring the installation surface is flat and clean.
5. Store the removed old parts properly.

2.2.2 Installing New Components

1. Ensure the installation orientation and angle of the new air filter match those of the old part.
2. Slowly position the new air filter into the mounting location within the air box. Adjust its placement to ensure a snug fit against the air box housing and any sealing surfaces. Verify there is no looseness or misalignment, and prevent interference with other parts.
3. Reinstall all fasteners (clamps, screws, etc.) in the reverse order of disassembly. Hand-tighten each connection until it is just loose. After confirming all connections are correctly installed, use tools to gradually tighten them to specification.
4. Exercise controlled force during tightening. Avoid over-tightening, which may damage threads or plastic air box components. Similarly, insufficient tightening may cause loosening and compromise filtration.
5. If fittings include accessories (e.g., sealing gaskets), ensure these are properly seated. Seals must lie flat without distortion or damage to prevent air leaks around the filter.

Image 2: Air Filter with accompanying sealing ring

2.3 Post-Installation Inspection

• Conduct a comprehensive inspection of all connections to ensure all components are securely fastened, accessories are fully installed, and no parts exhibit looseness, misalignment, or interference.
• Inspect surrounding ATV components to confirm no damage occurred during installation and all parts are properly positioned.
• If abnormalities are detected during inspection (e.g., loose components, air leaks around the filter housing), immediately cease use. Remove and reinstall the component, or contact a professional technician to troubleshoot the issue.

3. Operating Instructions

3.1 Precautions for First Use

• After installing the new air filter, it is recommended to conduct a short test ride (1-2 kilometers). During the test ride, pay close attention to engine performance, unusual noises, or signs of looseness around the air box.
• Avoid sudden acceleration or abrupt maneuvers during the test ride. Maintain steady riding to gradually allow the engine to adapt to the new air filter.
• After the short test ride, recheck the tightness of all air box fasteners. Tighten any loose parts immediately. Address any other abnormalities promptly. Only resume normal riding after confirming everything is in order.

3.2 Daily Usage Guidelines

• Before riding, always inspect the air filter housing to ensure no loose or damaged components.
• During riding, avoid prolonged operation in extremely dusty, muddy, or wet environments, as this can rapidly clog the air filter.
• Unauthorized modifications, substituting this air filter for parts of different models or specifications, or overloading components are strictly prohibited to prevent accidents.

4. Maintenance

• Cleaning: If the air filter accumulates mud, water, or dust after riding, promptly clean it according to your ATV's service manual recommendations for foam air filters. This typically involves washing with a suitable cleaner, rinsing, drying, and re-oiling (if applicable for your filter type) to prevent corrosion or damage and maintain filtration efficiency.
• Inspection: Regularly inspect the air filter for tears, holes, or excessive dirt buildup. Check the sealing surfaces for any signs of wear or damage that could allow unfiltered air into the engine.
• Replacement: Replace the air filter at recommended intervals specified in your ATV's service manual, or sooner if it appears damaged or excessively dirty and cannot be cleaned effectively.
• Protection: Avoid contact with corrosive substances that could degrade the foam material.

5. Troubleshooting

• Engine Performance Issues: If you notice a decrease in engine power, rough idling, or increased fuel consumption after air filter installation, first check for proper seating of the air filter and ensure the air box is sealed correctly. An improperly installed or clogged air filter can restrict airflow.
• Unusual Noises: If you hear whistling or sucking noises from the air box area, it may indicate an air leak. Re-inspect the air filter's seating and the air box seals.
• Loose Components: If any loosening of air box fasteners is detected, immediately stop the ATV, shut off the engine, investigate the issue, and address it by tightening the fasteners. Continuing to ride with loose components is strictly prohibited.
• Damage to Filter: If the air filter appears damaged (tears, holes) or excessively dirty, replace it immediately.
• Professional Assistance: If you cannot resolve the issue, contact a professional technician for diagnosis and repair.

6. Specifications

6.1 Compatibility List

This air filter is compatible with the following Yamaha ATV models:

• Yamaha Big Bear 350: 1987-1999 (YFM350FW 4x4, YFM350U 2x4)
• Yamaha Moto-4 350: 1987-1995 (YFM350ER)
• Yamaha Moto-4 250: 1989-1991 (YFM250)
• Yamaha Kodiak 400 4x4: 1993-1999 (YFM400FW)
• Yamaha Timberwolf 250: 1992-2000 (YFB250 2x4, YFB250FW 4x4)

7. Safety Warning

This section contains critical information. Please read it carefully and strictly adhere to the instructions to prevent accidents caused by improper operation, which could result in personal injury or property damage!!!

• During installation, ensure the ATV engine is turned off and the power is disconnected. The vehicle must be securely supported. Never install or remove parts while the engine is running.
• If you lack experience installing ATV parts, we recommend visiting a professional ATV repair shop for installation by a qualified technician. Do not attempt installation yourself to avoid malfunctions caused by incorrect installation.
• During installation and removal, never use tools that do not meet specifications. Never forcefully pry or install connectors to avoid damaging bolts, threads, accessories, or ATV components.
• After installing replacement parts, conduct a thorough inspection and take a short test ride. Only resume normal riding after confirming the accessory is securely installed and functioning properly. Never ride without passing inspection.
• If any loosening, abnormal noises, or malfunctions are detected during riding, immediately stop the ATV, shut off the engine, investigate the issue, and address it. Continuing to ride is strictly prohibited.
• Unauthorized modification of this product is prohibited. Using this product to replace parts of other models or specifications is prohibited. Continuing to use accessories that are damaged or aged is prohibited.
• During installation, use, and maintenance, wear protective gear (gloves, goggles, etc.) to prevent hand lacerations, injury from flying parts, burns from hot components, and other accidents.
• This product is exclusively compatible with specified Yamaha ATV models. Use on non-designated models is strictly prohibited, as it may cause component damage, ATV malfunction, and result in safety incidents.
• Children and minors are strictly prohibited from operating ATVs or engaging in the installation, removal, or maintenance of components to prevent accidents.

8. Warranty and Support

8.1 After-Sales Service

If you have any questions during the installation, use, or maintenance of this air filter, or if you discover any quality issues with the accessory, please contact your after-sales service team promptly. They will be happy to assist you.

Service Hours: Monday to Friday, 9:00 AM to 6:00 PM

8.2 Statement

This manual is intended solely as a reference for installation, operation, and maintenance. Should any discrepancies arise between the manual and the actual product due to ATV model updates or accessory upgrades, please refer to the physical product and dealer instructions. The company reserves the final right of interpretation regarding the contents of this manual. For any questions regarding the manual, please contact your after-sales service team.

Kindly note: Please keep this manual in a safe place for future reference and use.