Yoshimura · RS-12 · Slip-On
The Yoshimura RS-12 Stainless Slip-On Exhaust is a Signature Series Exhaust System built to complement the latest Honda CRF450 platform with a focused, race-ready design. This slip-on is designed for Honda CRF450R 2021–2024, Honda CRF450RX 2021–2024, and Honda CRF450R-S 2023–2024 (see the fitment table below).
Developed around an aggressive asymmetrical muffler profile and Yoshimura’s sound-management approach, the RS-12 is engineered to maximize capacity, add clearance at the tire and brake caliper, and support a precision fit. It includes the INS-32-K sound insert, with optional inserts and a spark arrester available separately.
Performance
The RS-12 uses an aggressive asymmetrical muffler shape designed to maximize capacity while improving clearance for the tire and brake caliper. Yoshimura also incorporates a resonance chamber intended to manage sound and help increase usable power for track or trail riding.
Engineering
A unique oval manifold design is created using an FEA process (Finite Element Analysis) and produced using a state-of-the-art hydroforming process. This engineering-led approach supports a purpose-built shape and consistency for the RS-12 system layout.
Fitment
RS-12 systems utilize precision machined joints for a superior, exacting fit. Yoshimura states the 360 degree contact surface better secures the seal between surfaces, translating into improved system life, fit and performance over time.
Development
Yoshimura developed the RS-12 system for the Honda CRF450 platform over more than a year, with testing and refinement aimed at motocross competition and off-road use. The project involved collaboration with Honda Japan, HRC Honda, and MXGP World Champion Tim Gajser, resulting in a slip-on designed to be ready for the race track and trails.
Sound
RS-12 incorporates a resonance chamber for managing sound, and it includes the INS-32-K sound insert. A patent pending Precision Taper Fit (PTF) insert ring is designed to make sound inserts and spark arresters easier to install and remove. For riders who want to tailor the setup, optional inserts and spark arresters are available, along with repack kits for ongoing maintenance.
Engineering
This RS-12 is specified in Stainless and features a works-look matte carbon fiber end cap with Yoshimura’s detailing. The carbon end cap cover uses an inner cap mounted design intended to improve durability and ease servicing compared to sandwich mounting designs. Yoshimura also uses a tapered muffler body inlet design that enables the system to be pushed forward to help with weight centralization without sacrificing performance.
Fitment
This slip-on exhaust is listed for Honda CRF450R 2021–2024, Honda CRF450R-S 2023–2024, and Honda CRF450RX 2021–2024. The page includes an installation PDF and a product video to support planning and installation. Sound insert and spark arrester options are shown on the page for reference, including what is included with this system.
| Part Number | 225852S320 |
|---|---|
| Brand | Yoshimura |
| Product Line | Signature Series Exhaust System |
| Series | RS-12 |
| System Type | Slip-On |
| Material | Stainless |
| Sound Insert (Included) | INS-32-K |
| Spark Arrester | Not included |
| Shipping Weight | 12 lb |
| Barcode | 00840025912243 |
| Emissions Compliance | QUALIFIED MANUFACTURER DECLARED "REPLACEMENT PART" |
| Make | Model | Model Years |
|---|---|---|
| Honda | CRF450R | 2021–2024 |
| Honda | CRF450R-S | 2023–2024 |
| Honda | CRF450RX | 2021–2024 |
Fitment as listed by Yoshimura for part number 225852S320.
| Part Number | Type | Included With This System |
|---|---|---|
| INS-32-K | Sound Insert | Yes |
| INS-34-K | Sound Insert | No |
| SA-21-K | Spark Arrester | No |
Instructions / What's Included (PDF)
Provided by Yoshimura. Opens in a new tab.
