Description

Honda CB/CBR 650F/R De-Cat Exhaust System (2017–2026)

One of our best-selling Austin Racing exhaust systems — and for good reason.

The Honda CB650 and CBR650 range is hugely popular with newer and LAMS riders, but the factory exhaust can leave the bike sounding far more restrained than its inline-four engine deserves. The Austin Racing De-Cat Exhaust System completely transforms the character of the bike, delivering the aggressive, high-revving exhaust note these engines are capable of producing.

This is not just a slip-on. It is a genuine de-cat system.

The factory catalytic converter/cat box is removed, while the original Honda headers remain in place. The result is a much freer-flowing system, substantial weight reduction and, most importantly for many owners, a dramatically louder and more engaging exhaust note compared with the standard system and conventional slip-ons.

If you want your CB or CBR 650 to actually sound like an inline-four, this is the system.

Why This System Is So Popular

• Proper De-Cat System: Removes the factory catalytic converter/cat box rather than simply replacing the muffler.
• Seriously Impressive Sound: A much deeper, louder and more aggressive exhaust note that comes alive as the revs climb.
• Full Titanium Construction: Lightweight, strong and highly resistant to heat.
• Only 1.2 kg: A significant reduction in weight compared with the bulky factory exhaust components.
• Retains OEM Headers: Keeps the original Honda headers in place while replacing the catalytic converter section and muffler.
• Removable Internal Baffles: Adjust the exhaust volume depending on your preference.
• Handmade to Order in the UK: Every system is individually produced by Austin Racing’s small specialist team — it isn’t a mass-produced, off-the-shelf exhaust.
• Choice of Austin Racing Mufflers: Select the can style, size and finish that best suits your bike.

The Sound

This is where the Austin Racing de-cat really separates itself from more basic exhaust options.

Removing the restrictive factory catalytic converter allows considerably more of the CB/CBR 650’s distinctive inline-four exhaust note to come through. At lower RPM it produces a deeper, more purposeful tone, while higher in the rev range it develops the sharp, aggressive Austin Racing sound the brand is known for.

For riders coming from their first standard or LAMS bike, the difference can be enormous.

Tested Noise Levels at 5,500 RPM

• Without dB Killer: 101 dB
• With dB Killer: 96 dB

This is a loud exhaust system, particularly with the baffle removed. Please consider your intended use and local regulations before ordering.

Muffler Options

Choose from several Austin Racing muffler designs:

GP1R
Compact 100 mm can with Austin Racing’s distinctive angular tip. Available in Black or Pure Titanium.

GP2
200 mm carbon can for riders wanting the classic Austin Racing carbon look.

GP2R
Ultra-compact 110 mm carbon can for an aggressive, minimal appearance.

V3
Available in 150 mm, 200 mm and 250 mm lengths, with Black Ceramic or Titanium finish options.

Austin Racing carbon sleeves are wrapped over a titanium construction for excellent strength and durability.

Installation — Please Read

This is a de-cat system and installation requires cutting and removing the original catalytic converter/cat box.

The original Honda headers remain fitted to the motorcycle, with the Austin Racing system connecting to the OEM headers once the factory catalytic converter section has been removed.

Full fitting instructions are provided.

Fitting Instructions

Handmade to Order — Not Mass Produced

An Austin Racing exhaust is very different from a mass-produced system sitting on a warehouse shelf.

Every exhaust is handmade to order in the UK by a small specialist team.

The titanium components are individually fabricated, assembled and finished specifically for your order. This labour-intensive manufacturing process is a major part of what makes Austin Racing exhausts distinctive, and it is why these systems are produced in limited numbers rather than mass manufactured.

Demand is consistently high, particularly for popular systems such as the CB/CBR 650 de-cat, so please allow for the quoted production timeframe when ordering.

For riders wanting something genuinely special rather than another mass-produced exhaust, the wait is part of getting a proper handcrafted Austin Racing system built specifically for your bike.

Specifications

• Fitment: Honda CB/CBR 650F/R, 2017–2026
• System Type: De-Cat
• Headers: Retains original OEM Honda headers
• Catalytic Converter: Factory catalytic converter/cat box removed
• Construction: Titanium
• System Weight: Approximately 1.2 kg
• Noise Level with dB Killer: 96 dB at 5,500 RPM
• Noise Level without dB Killer: 101 dB at 5,500 RPM
• Baffle: Removable
• Manufacture: Handmade to order in the UK

Important Notes:

Road Use: Non-homologated exhaust systems may not comply with local road regulations and are intended for race use only. Noise levels can vary significantly, from standard to extremely loud. Please review the specifications carefully before ordering. If you have any questions or need assistance, feel free to contact us.

Build Times: Our exhausts are built to order, with delivery times ranging from 6 to 10 weeks for standard systems and 10 to 15 weeks for more complex full systems. For the latest estimated delivery times, please visit Current Build Times. These timeframes reflect the handcrafted nature of our exhausts, which are produced by a small team in the UK, as well as the high demand for these limited products.

Exhaust Types: We offer three types of exhaust systems:

1. Slip-On Exhausts: These replace the bike’s original muffler, leaving the mid-section (catalytic converter) and headers untouched. Slip-ons are a straightforward option to enhance sound and aesthetics.
2. De-cat Systems: A decat system replaces both the muffler and the mid-section (catalytic converter), while keeping the original OEM headers in place. This offers improved performance and a noticeable weight reduction.
3. Full Systems: A full system replaces all three components: the muffler, mid-section (catalytic converter), and headers. This provides a complete overhaul for maximum performance and weight savings.

Each system is designed to cater to different performance, sound, and aesthetic goals. If you’re unsure which option suits your needs, feel free to reach out—we’re here to help!

Design Updates: As each exhaust is handmade to order, our designs are constantly evolving to incorporate improvements. As a result, the final product may vary slightly from the pictures shown. These differences are typically very minor and represent the ongoing enhancements we make to ensure the highest quality. This adaptability is one of the unique benefits of owning a handcrafted exhaust.