Yoshimura · RS-4
The Yoshimura RS-4 Replacement End Cap Kit is a complete service-parts solution for refreshing the end cap on compatible RS-4 mufflers. Designed for RS-4 mufflers with a standard 15 degree turn-down tip, this kit provides the key components needed to perform an end cap swap while maintaining the look and finish riders expect from the RS-4 series.
This kit is listed for applications including GasGas EX-250F 2023, GasGas EX-350F 2022–2023, Honda CRF450L-International 2019–2025, and select Yamaha WR and YZ models shown in the fitment table below. It is not compatible with RS-4S or RS-4T models.
Fitment
Built for RS-4 mufflers that use a standard 15 degree turn-down tip, this end cap kit targets the correct configuration for the RS-4 series. It is specifically noted as not compatible with RS-4S or RS-4T models, helping avoid mismatched parts when servicing an RS-4 muffler.
Materials
The replacement end cap is described as a heat resistant, pre-impregnated carbon fiber piece with a high-gloss finish.
Installation
This kit is intended to provide the parts needed for an end cap swap and includes a high-gloss carbon fiber end cap along with end-cap stickers, rivets, and rivet bands. It is a straightforward way to gather the core replacement items in one package.
Fitment
As part of Yoshimura’s Replacement Service Parts line, the RS-4 Replacement End Cap Kit supports routine maintenance and repair of RS-4 mufflers. It is meant for RS-4 mufflers using a standard 15 degree turn-down tip, making it a targeted option for restoring the end-cap area without replacing the entire muffler assembly. Compatibility is clearly defined as excluding RS-4S and RS-4T models.
Materials
Yoshimura describes the end cap as being made from heat resistant pre-impregnated carbon fiber with a high-gloss appearance. Manufactured in the brand’s composites shop in Chino, California, the kit is positioned as an OE-style replacement to keep an RS-4 muffler looking consistent after an end cap swap or repair.
Installation
This kit is listed for a range of model applications including select GasGas, Honda, and Yamaha fitments shown on the product page. Because RS-4 mufflers can vary by end cap configuration, Yoshimura notes that confirming the end cap setup is important to ensure proper application. An installation PDF is provided on the page to support the replacement process.
| Part Number | RS4-CFC-K-1 |
|---|---|
| Brand | Yoshimura |
| Product Line | Replacement Service Parts |
| Series | RS-4 |
| Shipping Weight | 1 lb |
| Barcode | 00840025911628 |
| Make | Model | Model Years |
|---|---|---|
| GasGas | EX-250F | 2023 |
| GasGas | EX-350F | 2022–2023 |
| GasGas | MC-250F | 2022–2023 |
| GasGas | MC-350F | 2022–2023 |
| GasGas | MC-450F | 2022–2023 |
| Honda | CRF450L-International | 2019–2025 |
| Yamaha | WR250F | 2020–2023 |
| Yamaha | WR450F | 2019–2022 |
| Yamaha | YZ250F | 2019–2026 |
| Yamaha | YZ250FX | 2020–2023 |
| Yamaha | YZ450F | 2018–2022 |
| Yamaha | YZ450FX | 2019–2022 |
Fitment as listed by Yoshimura for part number RS4-CFC-K-1.
Instructions / What's Included (PDF)
Provided by Yoshimura. Opens in a new tab.
