There seems to be some confusion when it comes to what is and isn’t acceptable for an exhaust system on a motorcycle or scooter.
The VOSA testing manual states that the motorcycle MUST not have any markings indicating that it not approved for standard road use, such as, ''not for road use'' or ''race use only''. The exhaust does not have to carry a BS or E mark, as long as it isn't excessively loud compared to the bike's original system.