⟲ 360° — drag meThe facts.
| Brand | SC-Project |
|---|---|
| Model | S1 Slip-On Silencer |
| Part Number | Y21A-L41T |
| Material — canister | Titanium |
| Material — end cap | Carbon fibre |
| Construction | T.I.G.-welded titanium with CNC-machined bushings |
| Homologation | EURO 4 road legal (db-killer included) |
| Performance gain | +2.8 hp at 14,000 rpm; +1.4 Nm at 12,000 rpm |
| Fitment | Yamaha YZF-R6 RJ27 (2017-2026) |
DescriptionThe whole story▼
If you want a genuine performance upgrade for your Yamaha YZF-R6 RJ27 that works equally well on your daily commute and your weekend track day, the SC-Project S1 Slip-On is the answer. Road-legal under EURO 4, it delivers a measured +2.8 hp at 14,000 rpm and +1.4 Nm of torque at 12,000 rpm — all wrapped in a titanium canister with a carbon end cap that weighs a fraction of the stock unit.
Key Features
- EURO 4 homologated for full road legality — includes db-killer for compliant, everyday use and can be removed for unrestricted track sound
- +2.8 hp at 14,000 rpm and +1.4 Nm at 12,000 rpm over the stock exhaust for sharper throttle response and stronger top-end pull
- Conical titanium canister with CNC-machined titanium bushings for precise fitment and long-term durability
- Carbon end cap with specialist heat-insulating material for outstanding thermal management at sustained high rpm
- T.I.G.-welded titanium joints throughout for a clean, race-quality finish that resists fatigue and corrosion
- Laser-engraved SC-Project logo — the same branding found on WorldSBK-specification machines
Everyday Usability Meets Racing Pedigree
The S1 range has earned its reputation as a reference-level exhaust in the Superbike World Championship, and this road-going version makes that technology accessible without compromise. With the db-killer installed, the note is deep and sporting — entirely at home in traffic while still announcing the R6's high-revving character. Remove it for a full, unfiltered MotoGP-style sound spectrum when conditions allow. The lightweight titanium and carbon construction trims unsprung and overall mass, directly benefiting agility and chassis feel through corners.
Construction & Materials
SC-Project builds the S1 to the same material standards used in professional racing. The conical titanium body is shaped for aerodynamic efficiency and minimal weight. Every joint is T.I.G.-welded for structural integrity and visual precision. CNC-machined titanium bushings ensure a rattle-free, exact fit to the R6's collector. The integrated carbon heat shield manages temperatures across sustained hard riding, protecting both the canister and surrounding bodywork. The result is an exhaust that improves with age rather than degrading — titanium does not corrode and holds its colour through heat cycles.
Sound Profile
With the db-killer in place the S1 produces a deep, aggressive tone that suits street riding and passes standard drive-by noise tests under EURO 4. With the db-killer removed the full exhaust note opens up — a raw, high-frequency wail that characterises the R6's inline-four at the top of its rev range. Both settings suit the same silencer; no additional components are required to switch between them.
Fitment & Compatibility
This slip-on silencer is a direct, bolt-on replacement for the stock unit on the following model:
- Yamaha YZF-R6 RJ27 — model years 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025, 2026
No modification to the header or collector is required. The titanium link pipe is included and connects directly to the existing mid-pipe.
Specifications
| Brand | SC-Project |
|---|---|
| Model | S1 Slip-On Silencer |
| Part Number | Y21A-L41T |
| Material — canister | Titanium |
| Material — end cap | Carbon fibre |
| Construction | T.I.G.-welded titanium with CNC-machined bushings |
| Homologation | EURO 4 road legal (db-killer included) |
| Performance gain | +2.8 hp at 14,000 rpm; +1.4 Nm at 12,000 rpm |
| Fitment | Yamaha YZF-R6 RJ27 (2017-2026) |
What's includedEverything in the box▼
- SC-Project S1 slip-on silencer — titanium with carbon end cap (Y21A-L41T)
- Mounting springs and bolts
- SC-Project laser logo
- SC-Project sticker set
- EURO 4 homologation card
- 24-month SC-Project official warranty
FitmentWhich bikes this fits▼
- Yamaha YZF-R6 RJ27 (2017–2026)
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