09 kawasaki klx 250 backfire

[Morbeca]

Hi guys! I just bought a 2009 kawasaki klx250 and I took it for a small ride on my street the other day and I noticed it was backfiring a lot. Should I be concerned? Or that happens with these bikes? It's my first dirt bike. Any help will be highly appreciated. Thank you

 

[Rotten_Ronnie]

Have you cleaned the air filter? Is it a stock pipe? I assume the back firing was on deceleration?

 

[Morbeca]

It is a stock pipe and yes it does backfire when i decelerate. I haven't cleaner the air filter. I will def try that
Thank you