Yoshimura · RS-4
The Yoshimura SOUND INSERT KIT 2M-MAX RS-4 Muffler, 1.375" is a 2-METER MAX replacement low-volume insert kit designed for Yoshimura RS-4 mufflers. It’s offered as an optional kit for applications that require different sound restrictions, helping tailor exhaust sound output to the specific setup.
This kit is listed for Honda CRF250R 2011–2013, KTM 350SX-F 2013–2015, KTM 350XC-F 2014–2015, KTM 450SX-F 2012–2014, and KTM 450SX-F-FACTORY-EDITION 2012. Decibel reduction depends on application; confirm fitment details using the insert chart and the fitment table shown on the page.
Built as a 2-METER MAX replacement low-volume insert kit for Yoshimura RS-4 mufflers, this setup is intended to support sound-restriction requirements where applicable. Because results vary by vehicle and configuration, the decibel reduction depends on the specific application.
The kit includes the low-volume insert tube, an end-cap collar, and a set screw. These components are provided together as a matched insert kit for RS-4 mufflers, making it a straightforward replacement or optional insert setup when different sound restrictions are needed.
This insert kit is specified as non-spark arrested. For riders selecting inserts based on required sound restrictions, this detail matters when choosing the appropriate configuration for a particular riding area or event requirements.
Sound
Yoshimura positions this as a low-volume insert solution for RS-4 mufflers, intended for applications where a different sound restriction is required. It serves as a replacement 2-METER MAX insert kit and is also described as an optional kit on certain applications. Since decibel reduction depends on application, selecting the correct insert is an important step in achieving the desired outcome.
Fitment
This insert kit is listed to fit Honda CRF250R 2011–2013, KTM 350SX-F 2013–2015, KTM 350XC-F 2014–2015, KTM 450SX-F 2012–2014, and KTM 450SX-F-FACTORY-EDITION 2012. Fitment should be confirmed using the insert chart referenced by the manufacturer, along with the fitment table provided on the page, before installation.
Included
Yoshimura supplies this insert kit with the key parts needed for the RS-4 muffler insert setup: a low-volume insert tube, an end-cap collar, and a set screw. An installation PDF is provided on the page for reference, helping ensure the insert components are assembled and secured as intended.
| Part Number | INS-2M26-K |
|---|---|
| Brand | Yoshimura |
| Product Line | Replacement Service Parts |
| Series | RS-4 |
| Shipping Weight | 0.5 lb |
| Barcode | 00840025914285 |
| Make | Model | Model Years |
|---|---|---|
| Honda | CRF250R | 2011–2013 |
| KTM | 350SX-F | 2013–2015 |
| KTM | 350XC-F | 2014–2015 |
| KTM | 450SX-F | 2012–2014 |
| KTM | 450SX-F-FACTORY-EDITION | 2012 |
Fitment as listed by Yoshimura for part number INS-2M26-K.
Instructions / What's Included (PDF)
Provided by Yoshimura. Opens in a new tab.
