Motorcycle With Aftermarket Exhaust and Loose Baffle

The vehicle is subject to the Noise Control Ordinance (Cap 400) and the Noise Control (Motor Vehicles) Regulations, which set noise limits and require vehicles to comply with the approved noise standard for their model. The Road Traffic (Construction and Maintenance of Vehicles) Regulations (Cap 374A) also require the exhaust system to be maintained so that it is not a nuisance and does not create excessive noise. A stationary reading of 94 dB(A) against an approved limit of 82 dB(A) is a clear exceedance of 12 dB(A), which is a major failure.

The "racing use only" certificate is not a road-use approval. It does not establish that the exhaust meets the type-approved noise limit, and it may even confirm that the item is not intended for road use. The absence of an approval mark and the loose baffle add to the concern: a loose baffle can rattle, change the noise level and potentially detach. The examiner should test the vehicle as presented. If the baffle was "in" but loose, the reading still represents the vehicle's condition at examination. The examiner should not accept the owner's claim without verifying the exhaust's markings and fitment.

Before accepting the reading, the examiner should confirm that the sound level meter is calibrated, the background noise is low enough, the microphone is at the specified distance and angle, the engine speed is correct, and the test area is suitable. The loose baffle may cause an unstable reading, so the examiner should note it and, if the procedure requires, repeat the test. However, a repeat test is unlikely to bring a 94 dB(A) exhaust below 82 dB(A) unless the baffle is properly secured and the exhaust is repacked or replaced. The test is valid if the conditions are met; the exceedance is a failure.

The aftermarket exhaust without an approval mark is a major modification/construction defect. The loose baffle is at least a major defect because of noise and detachment risk, and could be dangerous if it obstructs the wheel or brake. The non-standard rear mudguard may be a minor or major defect depending on its coverage and sharp edges; it must provide adequate spray protection. A very loud horn may also breach noise requirements, but the examiner should measure or assess it against the applicable standard rather than rely on impression. The motorcycle cannot be passed: the noise exceedance and unapproved exhaust are sufficient for a fail, and the loose baffle should be rectified before re-examination.

The record should include the measured noise level, the approved limit, the test speed and distance, the meter identification and calibration status, and the ambient conditions. It should describe the exhaust make or markings, the absence of an approval mark, the loose baffle, the non-standard mudguard and the horn. Photographs of the exhaust markings and baffle are useful. The owner's "racing use only" certificate should be noted but recorded as not accepted for road-use compliance. The result should be a fail with the defects classified.

The owner should be advised to fit an exhaust system that is approved for the model or otherwise demonstrated to meet the applicable noise standard, secure or replace the baffle, and ensure the mudguard provides adequate coverage without sharp edges. The horn should be checked against the applicable noise limit and replaced if necessary. The motorcycle should be re-presented with the approved exhaust and a stable, correctly fitted baffle. The examiner should not suggest that the owner simply refit the baffle temporarily for the test; the vehicle must comply in its normal road configuration. Any suspicion that the certificate is being used to disguise a non-compliant road exhaust should be recorded and escalated if the centre's procedure requires it.