Arrow 11013KZ Approved Catalyst Kit – Aprilia RS4 125 (2011-2016)

The Arrow 11013KZ catalyst kit is the catalytic converter that the Arrow catalog dedicates to the Aprilia RS4 125 produced from 2011 to 2016 (vehicle type TW). It is the component that validates the type-approval of the Arrow system: without a catalyst, the exhaust is not approved for road use. Product code 11013KZ.

✓ Strengths

• It is the part that keeps the bike street-legal – the Arrow catalog warns that the type-approval is only valid with the catalyst present in the system
• Combined in the catalog with the Thunder 51509AO silencer – these are the only two codes on the Arrow page for the RS4 125
• Components interchangeable with the original ones – it is installed in place of the corresponding stock section
• Original Arrow spare part – produced in Italy by Arrow Special Parts
• Unique code for the entire generation – covers the RS4 125 from 2011 to 2016, in all versions

Technical features

Vehicle compatibility

The list is taken from the manufacturer's official catalog. If you have any doubts, send us your bike's VIN and we will check the correct code for you.

Who it is perfect for

It is the part needed for those who install an Arrow exhaust on their Aprilia RS4 125 and want to stay street-legal: without the catalyst, the system loses its type-approval, and the difference is noticeable during the vehicle inspection. It is also useful for those who have had an Arrow system installed for years and need to replace the catalyst, for example due to clogging or in preparation for an emissions test.

Frequently asked questions

Which bikes is the Arrow 11013KZ catalyst installed on?
The official Arrow catalog dedicates it to the Aprilia RS4 125 produced from 2011 to 2016, identified by vehicle type TW. There are only two codes on that catalog page: this catalyst and the Thunder 51509AO silencer. When in doubt, send us your VIN before ordering.

What exactly is the catalyst for?
It is the component that reduces emissions and makes the Arrow exhaust system type-approved. The catalog states this explicitly with a warning in red: the type-approval is only valid with the catalyst present. Without it, the motorcycle is not compliant for road use.

Is the silencer included?
No: the package contains only the 11013KZ catalyst kit. The 51509AO aluminum Thunder silencer is a separate code in the Arrow catalog and is sold separately. If you need that as well, write to us and we can tell you if it is in stock.

Can I install it with the original exhaust?
Arrow indicates that its components are interchangeable with the original ones, so the catalyst fits in the same position as the corresponding stock section. However, the combination provided by the catalog for this bike remains the one with the Arrow 51509AO silencer.

Does it have a port for the lambda probe or a db-killer?
No, neither. The Arrow catalog states for this code: lambda probe: no, CO probe: no, and db-killer: not provided. The db-killer concerns the silencer, not the catalyst, and is an accessory for other exhaust lines.

What material is it made of and how much does it weigh?
Arrow does not publish the alloy or the dimensions of this catalyst: for this reason, the datasheet simply indicates metal. The body is a metal cylinder enclosing the catalytic honeycomb. The weight declared by the manufacturer is 0.5 kg.