Yoshimura · RS-9
The Yoshimura Sound Insert Kit for RS-9 and RS-9T mufflers is a low-volume insert solution designed to fine-tune exhaust sound while supporting performance goals. Yoshimura developed this insert to optimize sound and performance for the 2020 Honda CRF250R, and notes that it also works in all RS-9 and RS-9T mufflers.
This kit is listed for Honda CRF250R 2018–2021, Honda CRF250RX 2020–2021, Honda CRF450R 2013–2015, and KTM RC390 2015. For application-specific confirmation, reference the fitment table and insert chart shown on the page.
Designed as a low-volume insert kit for RS-9 and RS-9T mufflers, this setup offers an alternative for applications that require different sound restrictions. Yoshimura notes that decibel reduction will vary depending on the specific application.
This insert kit is identified as non-spark arrested. It is intended for riders who need a lower-volume configuration while using an RS-9 or RS-9T muffler, without changing the core muffler assembly.
The kit includes the low-volume insert tube along with an end-cap collar and a set screw. These components are designed to work together as a service-part solution for RS-9 and RS-9T muffler configurations.
Sound
Yoshimura positions this insert as a way to optimize sound and performance for the 2020 Honda CRF250R while maintaining compatibility across RS-9 and RS-9T mufflers. It serves as an optional configuration for riders who need to adapt to different sound restrictions without replacing the muffler, with results that can vary by application.
Fitment
This Yoshimura RS-9 series insert kit is listed for Honda CRF250R 2018–2021, Honda CRF250RX 2020–2021, Honda CRF450R 2013–2015, and KTM RC390 2015. Because insert selection can depend on the exact setup, the page includes an insert chart and fitment table to help confirm the correct application before installation.
Installation
An installation PDF is provided on the product page to guide setup of the insert components. The kit format centers on a low-volume insert tube, end-cap collar, and set screw, offering a straightforward service-part approach for RS-9 and RS-9T muffler owners who want a different sound configuration.
| Part Number | INS-RS9D-K |
|---|---|
| Brand | Yoshimura |
| Product Line | Replacement Service Parts |
| Series | RS-9 |
| Shipping Weight | 1 lb |
| Barcode | 00840025910447 |
| Make | Model | Model Years |
|---|---|---|
| Honda | CRF250R | 2018–2021 |
| Honda | CRF250RX | 2020–2021 |
| Honda | CRF450R | 2013–2015 |
| KTM | RC390 | 2015 |
Fitment as listed by Yoshimura for part number INS-RS9D-K.
Instructions / What's Included (PDF)
Provided by Yoshimura. Opens in a new tab.
