Aftermarket motorcycle exhausts can be legal or illegal in the UK, depending on certain factors. In general, any modification to a vehicle, including its exhaust system, must comply with the laws and regulations set by the government. Here are a few points to consider:
Noise Regulations: The UK has specific regulations regarding the noise emitted by motorcycles. Exhaust systems must meet certain noise limits specified by the European Union or have an appropriate noise reduction system fitted. If an aftermarket exhaust system exceeds the noise limits, it could be considered illegal.
Type Approval: In the UK, motorcycle exhaust systems must have the appropriate type approval to be legal. This means they need to meet specific standards and have the necessary markings to demonstrate compliance. Aftermarket exhausts that do not have the required type approval may be considered illegal.
Emissions Regulations: Motorcycle exhaust systems must also comply with emissions regulations. Aftermarket exhausts should not significantly increase emissions beyond the legal limits. If an exhaust system affects the emissions in a way that violates regulations, it could be deemed illegal.
MOT Test: During the annual MOT (Ministry of Transport) test, motorcycles are checked for roadworthiness and compliance with regulations. If the exhaust system is found to be non-compliant during the MOT test, it may need to be replaced or modified to meet the requirements.
It's essential to consult the specific regulations and guidelines set by the UK government's Vehicle Certification Agency (VCA) or consult with a knowledgeable professional to ensure compliance with the law. Remember that illegal modifications can result in penalties, fines, or even the vehicle being declared unroadworthy.