⟲ 360° — drag meThe facts.
| Brand | Akrapovic |
|---|---|
| Part number | S-B13SO4-HJGT |
| Fitment | BMW R 1300 GS / GS Adventure (2024–2026), R 1300 R / RS (2025–2026) |
| System type | Slip-on silencer, double flow |
| Materials | Titanium muffler, handmade carbon fibre end cap |
| Weight | 2.05 kg (stock 2.26 kg, saving 0.21 kg / 9.3 %) |
| Power | 145.5 PS at 7,800 rpm (stock 143.8 PS, gain 1.9 PS / 1.4 kW at 7,600 rpm) |
| Torque | 148.8 Nm (stock 148.5 Nm, gain 4.5 Nm at 2,300 rpm) |
| Installation time | Approx. 20 minutes |
| Road approval | EC type approval and ECE type approval |
DescriptionThe whole story▼
The R 1300 GS carries the strongest boxer BMW has ever built, and its standard silencer was shaped to keep that engine quiet rather than to show what it can do. The Akrapovic Slip-On Line (Titanium), part number S-B13SO4-HJGT, replaces it with a double-flow titanium muffler that adds 4.5 Nm at 2,300 rpm — exactly where a fully loaded GS leaves a junction or crawls up a gravel switchback — and it does so with EC and ECE type approval, so nothing changes in the vehicle documents.
Key Features
- Double-flow muffler body in lightweight titanium, closed by a handmade carbon fibre end cap
- 4.5 Nm more torque at 2,300 rpm and 1.9 PS (1.4 kW) more power at 7,600 rpm, measured back to back against the standard system on the Akrapovic dyno
- 2.05 kg instead of 2.26 kg — 9.3 % off the stock silencer, and all of it high and far back on the bike
- Profiled muffler surface that adds structural stiffness and resists the stone chips a GS collects, finished with an engraved Akrapovic logo
- EC and ECE type approved, so the system is road legal across Europe with the certificates supplied
- Fully compatible with the BMW Motorrad side cases — the touring set-up stays exactly as it was
- Plug-and-play installation in about 20 minutes with no remapping needed
Construction and Material Quality
Titanium is the reason this silencer weighs what it does. Akrapovic melts and processes it in-house, which is unusual even among premium exhaust manufacturers, and the double-flow internal layout means the gas path splits rather than being forced through a single restrictive chamber. The profiled outer surface is not decoration: the pressed contour stiffens a thin-walled tube that would otherwise dent, which matters on a machine that spends its life next to panniers, boots and the occasional dropped bike.
The end cap is carbon fibre, laid up and trimmed by hand. Against the raw titanium it gives the tail of the GS the visual weight the standard plastic-shrouded silencer never had, and it will not corrode or discolour under the heat load of a heavily loaded boxer working hard in summer traffic.
Performance and Sound
The headline number here is torque, not peak power. Akrapovic recorded 4.5 Nm more at 2,300 rpm, which on a 1,300 cc boxer is the difference between short-shifting comfortably and having to keep the revs up. Peak power rises from 143.8 PS to 145.5 PS and arrives 200 rpm earlier, and the peak torque figure of 148.8 Nm is essentially unchanged from stock — this system was developed to fill the bottom of the range rather than to chase a dyno headline.
The sound is deliberately restrained. Because the system holds EC and ECE approval it stays inside the legal noise window, but the double-flow design gives the boxer a deeper, fuller beat at low revs than the standard unit allows, without the drone that makes long days uncomfortable.
Fitment and Compatibility
S-B13SO4-HJGT is developed for the BMW R 1300 GS and R 1300 GS Adventure from model year 2024, and for the R 1300 R and R 1300 RS from model year 2025. It connects to the original header, needs no modification to the manifold, and takes about twenty minutes with hand tools. The BMW Motorrad side case system fits over it unchanged.
Akrapovic offers an optional titanium header (E-B13E1) and a carbon fibre heat shield (P-HSB13SO1) for this machine. Both are separate items; neither is required to run the slip-on, and fitting the optional header cancels the type approval of the silencer.
Road Approval
This system carries EC type approval and ECE type approval. The certificates are supplied with the exhaust and are also available as downloads on this page. It is a legal replacement silencer for road use in the European Union, and no entry in the vehicle documents is required as long as the certificate is carried with the bike.
Specifications
- Part number: S-B13SO4-HJGT
- EAN: 3831126428969
- Fitment: BMW R 1300 GS / GS Adventure (2024–2026), R 1300 R / RS (2025–2026)
- System type: slip-on silencer, double flow
- Muffler material: titanium
- End cap: carbon fibre, handmade
- System weight: 2.05 kg (stock 2.26 kg, saving 0.21 kg / 9.3 %)
- Power: 145.5 PS at 7,800 rpm (stock 143.8 PS at 8,000 rpm, gain 1.9 PS / 1.4 kW at 7,600 rpm)
- Torque: 148.8 Nm (stock 148.5 Nm, gain 4.5 Nm at 2,300 rpm)
- Remapping: not required
- Installation time: approx. 20 minutes
- Side case compatible: yes, BMW Motorrad system cases
- Road approval: EC type approval and ECE type approval
- Country of manufacture: Slovenia
FitmentWhich bikes this fits▼
- BMW R 1300 GS (2024–2026)
- BMW R 1300 GS Adventure (2024–2026)
- BMW R 1300 R (2025–2026)
- BMW R 1300 RS (2025–2026)
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