KTM Duke Exhaust Upgrades: Best Slip-On Options for the 125, 250, 390, and 690

by Euro Motards Performance

The KTM Duke is one of the best-selling naked bike lines globally, and for good reason. Whether it's the accessible Duke 125 for new riders, the sharp Duke 390 for sport-oriented commuters, or the torquey single-cylinder Duke 690 for experienced riders who want a lightweight weapon, the Duke family covers huge ground.

What they all share is a passionate owner community and strong aftermarket support — particularly for exhaust systems. Here's a breakdown of what to look for when upgrading the exhaust on any Duke model.

Why Duke Owners Upgrade Their Exhausts

The stock KTM Duke exhaust, like most modern production bike exhausts, is designed to pass noise and emissions regulations in multiple markets. This means it's heavier and more restricted than it needs to be from a pure performance standpoint.

The main reasons Duke owners upgrade:

  • Sound — the stock Duke exhaust is notably quiet, particularly on the single-cylinder 125, 250, and 390 models. An aftermarket slip-on unlocks a much more characterful thump.
  • Weight — the stock exhausts are relatively heavy for the bike's size. A quality slip-on can save 1.5–3 kg, which on a 148 kg (Duke 390) or 150 kg (Duke 690) bike is meaningful.
  • Looks — the stock exhaust can look bulky compared to the sharp, angular lines of the Duke bodywork. A compact stainless or titanium can significantly improves the visual balance.

GPR Exhausts for the KTM Duke Range

GPR produces one of the most comprehensive Duke exhaust ranges available, covering the 125, 250, 390, and 690 across multiple model years. Their Duke-specific offerings include:

Duke 125 / 250 (2017+)

The smaller Duke models are popular in Europe where they're used as everyday commuters. GPR's Furore Carbon Fibre slip-on is one of the most popular choices — compact, carbon-capped, and road-legal. It dramatically changes the sound character from the very muted stock pipe to something with a genuine single-cylinder bark.

Duke 390 (2013+)

The Duke 390 has seen significant evolution across its generations (Gen 1 2013–2016, Gen 2 2017–2022, Gen 3 2023+). Each generation has different exhaust routing, so check fitment carefully by year. GPR offers both the Furore series and the higher-spec GPE titanium series for the 390, with road-legal versions in both.

Duke 690 (2008+)

The 690 is the big single — a 72 hp, 698cc thumper that's arguably the most characterful Duke. The stock exhaust on the 690 is particularly large and heavy relative to the rest of the bike. GPR's full exhaust systems for the 690 include a 2-in-1 configuration in titanium that dramatically transforms the look and sound of the bike, with significant weight saving over the stock unit.

Road-Legal vs. Race Exhausts: What's Right for Your Duke?

This is particularly important on the Duke because many KTM owners use their bikes in both road and track contexts.

For a road-used Duke, you need a road-legal (homologated) system. These come with an EC type approval certificate and meet noise limits. GPR's homologated systems are legal in EU and UK and are clearly marked as such.

For a track-only or race Duke, a decatalised or non-homologated race system removes the catalyst and internal baffling for maximum flow and sound. These should not be used on public roads.

Some GPR systems include a removable noise insert that allows you to comply with noise requirements on road while removing it for track days — this is the most flexible option if you do both.

Fitment Notes for Duke Owners

KTM updates the Duke range frequently. Key fitment considerations:

  • The Duke 390 Gen 1 (2013–2016), Gen 2 (2017–2022), and Gen 3 (2023+) all have different exhaust specs
  • The Duke 250 (introduced 2017) shares some architecture with the 390 but has different exhaust fitment
  • The Duke 125 is a separate chassis from the 250/390
  • The Duke 690 R has different exhaust mounting from the standard 690

Always verify your exact model year and variant before ordering. If in doubt, contact us at sales@euromotards.com with your full bike details.

Installation

Slip-on exhausts for the KTM Duke range are designed for home installation:

  • Remove the OEM clamp and silencer from the mid-pipe
  • On some models, a heat shield on the right side panel needs to be removed first
  • Slide the new silencer onto the mid-pipe and torque the clamp to spec
  • On the 390 and 690, check whether the new system requires the O2 sensor bung to be used or blanked off

Browse our full range of KTM Duke exhaust systems at Euro Motards Performance, with fitment-verified listings for the 125, 250, 390, and 690 across all major model years.

Back to News