
The facts.
| Brand | Akrapovic |
|---|---|
| Part number | S-Y4MET17-FDHLTA |
| Fitment | Yamaha YZ450F (2026 model year only) |
| Line | Evolution Line (Titanium) — complete system |
| Weight | 3.32 kg (stock 4.17 kg, saving 0.85 kg) |
| Power | 56.6 PS (stock 54.7 PS, at 10,600 rpm) |
| Torque | 45.8 Nm (stock 45.5 Nm) |
| Predecessor | S-Y4MET16-FDHLTA for 2023–2025 |
| Road approval | None — closed course competition use only |
DescriptionThe whole story▼
One model year. Akrapovic lists this system for the 2026 YZ450F alone, and gives it the same published figures as the 2023–2025 article: 56.6 PS, 45.8 Nm, 3.32 kg. Different part, different mounting, same numbers.
Key Features
- Titanium complete system for the 2026 model year YZ450F
- 56.6 PS at 10,600 rpm, 45.8 Nm
- 3.32 kg instead of the standard 4.17 kg
- Listed for one model year only
- Priced slightly below the 2023–2025 article
Why a new part number for one year
A new part number in Akrapovic's catalogue usually means the mounting points, the header routing or the silencer position changed. The published performance figures are carried over unchanged, which suggests the engine is not what moved — the chassis around it is.
We report that as what it is: an observation from the data, not a statement from Yamaha. What is certain is that Akrapovic lists two different articles for 2025 and 2026, so the model year has to be right when ordering.
Check the year before ordering
A 2025 YZ450F takes S-Y4MET16-FDHLTA. A 2026 takes this one. They are not interchangeable, and the difference is not visible in the published figures — only in the part number.
Not for the road
Closed course competition only. No EC or ECE approval.
Buying for a bike that is barely out
A system listed for a single model year is usually a system for a machine that has just changed. Ordering one for a 2026 YZ450F means the bike is new, the standard exhaust has done very little, and the case for replacing it is weight rather than wear.
At 850 grams and 1.9 horsepower, that case is the same one the 2023–2025 system makes. Akrapovic carried the figures across unchanged, which is itself informative: the engine is not what moved.
What changed and what did not
We can say with certainty that Akrapovic issued a new part number, and that the published performance and weight figures are identical to the previous article. We cannot say from the manufacturer's data exactly which mounting point or routing changed, and we are not going to speculate about it in a product description.
If you are working on a build and need to know whether a 2025 system can be adapted, ask us and we will put the question to Akrapovic rather than guess.
Titanium and the first season
A new titanium system will change colour where it runs hottest within the first few hours — bronze near the head, blue further down. That is the metal annealing, it is expected, and it is not a fault. Cleaning it off with an abrasive removes the oxide layer that protects the surface.
Not for the road
Closed course competition only, and a 2026 YZ450F has no road registration in any case. The system carries no EC or ECE approval.
Ordering by frame number
Model years overlap with calendar years in motocross: a 2026 machine is often sold in the autumn of 2025. The frame number is what settles it, and it is worth reading before ordering a system that exists for one year only.
Article number
Akrapovic lists this system as S-Y4MET17-FDHLTA.
DownloadsInstructions▼
FitmentWhich bikes this fits▼
- Yamaha YZ450F (2026)
- Complete titanium system
- Closed course competition use only
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