Yoshimura · RS-4
The Yoshimura SOUND INSERT KIT RS-4 Muffler, 1.500" RING (INS-21-K) is a replacement low-volume insert kit designed for RS-4 mufflers. Built as a Replacement Service Parts offering, it provides an optional way to tailor exhaust sound restrictions on applications that require a different sound level.
This kit is non-spark arrested, and the amount of decibel reduction depends on the specific application. For correct application matching, refer to the insert chart and the specifications shown on the page.
Designed as a replacement low-volume insert kit for Yoshimura RS-4 mufflers, INS-21-K supports riders who need an insert solution for service or maintenance. It is also offered as an optional kit on applications that call for different sound restrictions.
INS-21-K is specified as non-spark arrested. This detail is important when choosing components for a particular riding area or requirement, and it helps ensure the correct insert style is selected for the intended use.
The kit includes the low-volume insert tube, an end-cap collar, and a set screw. These components are intended to work together as the insert assembly for RS-4 mufflers, helping restore or configure the muffler insert arrangement as needed.
Sound
As part of Yoshimura’s Replacement Service Parts line for the RS-4 series, INS-21-K is intended specifically as a low-volume insert kit for RS-4 mufflers. It can be used as a replacement insert solution and is also available as an optional kit on applications that require different sound restrictions, keeping the insert choice aligned with the needs of the application.
Fitment
Yoshimura notes that this is a low-volume insert kit and that decibel reduction depends on the application. Because sound results vary, the insert chart should be used to confirm correct fitment for the intended setup before installation. This helps ensure the correct insert style and configuration are selected for the muffler and application requirements.
Included
INS-21-K consists of the low-volume insert tube, end-cap collar, and set screw. An installation PDF is provided on the page to support proper setup. For riders working with multiple configurations, the insert chart is the recommended reference to verify the correct match for the specific application.
| Part Number | INS-21-K |
|---|---|
| Brand | Yoshimura |
| Product Line | Replacement Service Parts |
| Series | RS-4 |
| Shipping Weight | 0.4 lb |
| Barcode | 00840025908772 |
Instructions / What's Included (PDF)
Provided by Yoshimura. Opens in a new tab.
