The sound produced by your 125cc Honda Grom with an aftermarket exhaust, particularly without a baffle, can significantly impact its exhaust note and create unique auditory characteristics. Depending on the specific design and construction of the aftermarket exhaust, as well as the removal of the baffle, the resulting sound can be louder, more aggressive, or have a distinct tonal quality.
In your case, you mention that the idling sound of your modified Honda Grom resembles the sound of a Huey military helicopter. While it's challenging to provide an exact explanation without experiencing the sound firsthand, there are a few potential reasons why the two sounds may have similarities:
Frequency Range: The exhaust note of your modified Honda Grom, particularly without a baffle, may produce sound frequencies that overlap with those emitted by a Huey helicopter. This can create a perception of similarity between the two sounds.
Exhaust Design: Aftermarket exhaust systems are designed to enhance performance and alter the sound profile of the motorcycle. The specific design and internal components of the exhaust system, such as the shape of the pipes and the presence or absence of a baffle, can influence the exhaust note and potentially produce tones reminiscent of other sounds, like a helicopter.
Personal Perception: Sound perception can be subjective, and individuals may make unique associations between different sounds based on their personal experiences, memories, or cultural references. It's possible that the particular idling sound of your modified Honda Grom resonates with the sound characteristics of a Huey helicopter in your perception.
It's important to note that modifying your motorcycle's exhaust system can have legal implications, including noise restrictions and emissions compliance, depending on the regulations in your jurisdiction. Always ensure that any modifications you make to your motorcycle comply with local laws and regulations.
If you have concerns about the sound or performance of your modified Honda Grom, it's recommended to consult with an experienced mechanic or motorcycle specialist who can evaluate the exhaust system and provide further insights or recommendations.