1. Introduction
The HMS R300 Stainless Steel Exhaust System is designed to enhance the performance and aesthetics of your Yamaha NMAX 125 or NMAX 155. This manual provides essential information for proper installation, operation, and maintenance of the exhaust system. Please read these instructions carefully before installation and use.
2. Compatibility
This exhaust system is compatible with the following Yamaha models:
- Yamaha NMAX125/NMAX155 (Model Codes: 8BJ-SEG6J / 8BK-SG66J)
- Yamaha NMAX125 (Model Code: 8BJ-SEL1J)
- Yamaha Cygnus Gryphus (Model Code: 8BJ-SEJ4J)
- Yamaha X FORCE (Model Code: 8BK-SG79J)
Applicable Years: 2021-2024 models, and 2025 model NMAX125.
Important Note: This product is compatible with models featuring one O2 sensor. It is not compatible with Yamaha NMAX155 (8BK-SG92J).
3. Package Contents
Please verify that all the following components are included in your package:
- Silencer: 1 pc
- Exhaust Pipe: 1 pc
- Silencer Band (for 90φ): 2 pcs
- Baffle (standard equipment): 1 pc
- Dedicated Stay: 1 pc
- Flange Bolt M8x50: 2 pcs
- Cap Bolt M10x40: 2 pcs
- Cap Bolt M10x20: 1 pc
- M8 Nut: 2 pcs
- Spring: 2 pcs
4. Setup (Installation)
Important Safety Information:
- Installation of this product should be performed by a qualified professional mechanic. Refer to the included installation instructions or your vehicle's service manual.
- If you are installing the product yourself and have any questions or encounter difficulties, please consult a professional before proceeding.
- Product damage or external damage to the vehicle caused by improper installation will not be covered under warranty.
- Do not dispose of the removed genuine exhaust system or mounting bolts. Store them for potential future use.
Installation Overview
The following images illustrate the installed HMS R300 exhaust system on a Yamaha NMAX. Use these as a visual guide during your installation process, in conjunction with detailed instructions provided separately or in your vehicle's service manual.
5. Operating Considerations
After the engine starts, the exhaust system and surrounding components will become extremely hot. Exercise extreme caution to prevent burns. Avoid touching the exhaust system immediately after operation.
6. Maintenance
Over long periods of use, the sound-absorbing material (glass wool) inside the silencer may deteriorate, leading to increased noise levels. In such cases, it is recommended to replace the sound-absorbing material or replace the silencer with a new one. Please consult us if you require assistance with this maintenance.
7. Troubleshooting
If you experience any issues after installation, such as unusual noises or exhaust leaks, first verify the following:
- Ensure all bolts and nuts are securely tightened according to the installation instructions.
- Check that all connections between the exhaust pipe and silencer are properly seated and sealed.
- Inspect the exhaust system for any visible damage or cracks.
If problems persist after checking these points, it is recommended to consult a professional mechanic for diagnosis and repair.
8. Specifications
| Manufacturer Model Number | R300-364 |
| Silencer Overall Length | 400 mm |
| Silencer Body Length | 300 mm |
| Silencer Outlet Diameter | 60.5φ (2P Slash) |
| Silencer Inlet Diameter | Inner diameter 50.8φ |
| Baffle Outer Diameter | 57.5φ |
| Silencer Diameter | 90φ |
| Material | Stainless Steel |
| Product Weight | 3.1 kg |
| Country of Origin | Japan |
9. Important Notes
- This product is an exhaust system component and not a complete vehicle.
- Always confirm the compatibility (vehicle model, year, and type) before purchasing. If you are unsure, please consult us in advance.
- This product does not possess government certification.
- Returns for initial product defects may be accommodated depending on the specific situation. Please contact us for assistance.
- Returns or exchanges cannot be accepted for issues arising from customer installation errors, damage during vehicle operation, or incorrect purchases due to misidentification of vehicle model, year, or type.
- Full refunds are not possible for returns initiated due to customer convenience, even if the product is unopened.
- Returns are not accepted after the product has been opened, installed, the engine started, or the vehicle operated.
- Shipping and customer inquiry responses may be delayed on Saturdays, Sundays, national holidays, and during consecutive holiday periods.
10. Support
For any questions, concerns, or assistance regarding this product, please feel free to contact Nattyworks studio, the seller of this product.
Warranty: No specific warranty description is provided for this product.