anyone know what this is

[Hammer trx450r]

i was riding hard right after oil change when i noticed the bike got louder. I'm a 2 stroke guy so maybe someone can shed light on this for me. didnt seem to lose power or anything like that

[Hammer trx450r]

were are my mechanics at? where is 2004trx450r at when ya need him

[Pvt. Maggot]

if your running an aftermarket pipe..some of the packing might have got blown out...-shrugs-

[Hammer trx450r]

its a stock with hrc kit end cap

[Syrus]

Air box lid popped off ? does it still run loud when u start it up now ?

where does noise sounds like coming from? engine or exhaust?

[Hammer trx450r]

exhaust. Let me go check and see if airboot came off. good one with air lid poped off but no