Akrapovic exhaust Yamaha MT-125 S-Y125R4-HRT⟲ 360° — drag me
3.0 k g
02 · Data & docs

The facts.

Technical data
BrandAkrapovic
Part numberS-Y125R4-HRT
FitmentYamaha MT-125 and YZF-R125 (2014–2019)
LineRacing Line (Titanium) — complete system
MaterialTitanium
Weight3.0 kg (stock 4.7 kg, saving 1.7 kg / 36.2 %)
Power13.6 PS (stock 13.1 PS, gain 0.6 PS at 9,200 rpm)
Torque11.8 Nm (stock 11.6 Nm, gain 1.2 Nm at 3,350 rpm)
InstallationApprox. 45 minutes
Road approvalEC type approval — valid ONLY with the catalytic converter installed
DescriptionThe whole story▼

Read the approval line before anything else. Akrapovic states that the EC type approval for this system is valid only when the catalytic converter is installed. Remove it and the exhaust is no longer road legal — the approval and the converter are one package.

Key Features

  • EC type approval, valid only with the catalytic converter fitted
  • Complete titanium racing system
  • 3.0 kg against the standard 4.7 kg: 1.7 kg and 36.2 per cent less
  • 1.2 Nm more at 3,350 rpm — very low in the range
  • 13.6 PS, up from 13.1 PS
  • Among the smallest engines in this catalogue
  • Forty-five minutes to fit

Thirteen Horsepower

A learner 125 is limited by law to 15 PS, and Yamaha's MT-125 and R125 make 13.1 in this generation. There is no headroom to unlock, and Akrapovic does not claim any: 0.6 PS is what a complete titanium racing system delivers on an engine already at its legal ceiling.

What it does deliver is 1.2 Nm at 3,350 rpm and 1.7 kg less weight, on a motorcycle that weighs about 140. Proportionally that is more than it sounds.

What a 125 Rider Actually Buys

Sound and appearance, mostly, and this page will say so. A full titanium Akrapovic system on a learner bike is not a performance decision — 0.6 PS is inside measurement noise for a rider.

It is a first motorcycle, often the only one someone owns for two or three years, and the exhaust is the single most visible change available. The approval means it can stay on the bike legally, which on a 125 ridden to school or work matters more than on anything else in this catalogue.

The Catalytic Converter Stays

This is the condition and it is worth repeating. The system ships with a catalytic converter and the EC approval covers it in that state. Taking the converter out is a modification the approval does not cover, and it turns a legal exhaust into a track part.

Ten Images, and Why That Matters Here

Akrapovic publishes more photographs of this system than of almost anything else in its road catalogue. That is not an accident: a 125 buyer chooses on appearance, and the manufacturer knows it.

A Complete System on a Learner Bike

This is not a slip-on. The headers, the mid-section and the silencer all come off and are replaced, which is why fitting takes forty-five minutes rather than fifteen — and why the standard exhaust should go into a box rather than a skip.

A 125 is almost always sold on after two or three years, and a complete original exhaust is worth real money at that point.

Thirty-Six Per Cent on a 125

1.7 kg from a 4.7 kg standard system. Yamaha builds the MT-125's exhaust to a price and to a noise limit, and both push it towards heavy steel. A full titanium replacement takes more than a third of it away.

Fitment and Compatibility

S-Y125R4-HRT covers the Yamaha MT-125 and YZF-R125 from 2014 through 2019. Yamaha revised both for 2020, and those machines take a different system.

Specifications

  • Part number: S-Y125R4-HRT
  • EAN: 3831113547598
  • Fitment: Yamaha MT-125, YZF-R125 (2014–2019)
  • Line: Racing Line (Titanium), complete system
  • Material: titanium
  • Weight: 3.0 kg (stock 4.7 kg, saving 1.7 kg / 36.2 %)
  • Power: 13.6 PS (stock 13.1 PS, gain 0.6 PS at 9,200 rpm)
  • Torque: 11.8 Nm (stock 11.6 Nm, gain 1.2 Nm at 3,350 rpm)
  • Installation time: approx. 45 minutes
  • Road approval: EC type approval, valid only with the catalytic converter installed
  • Country of manufacture: Slovenia
DownloadsInstructions▼
FitmentWhich bikes this fits▼
  • Yamaha MT-125 (2014–2019)
  • Yamaha YZF-R125 (2014–2019)
07 · Support

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