Drilled exhaust sound change question

[Marcin]

I write a new topic but if U think it will be better connected to other than please do so.
I drilled my exhaust a couple of months ago and noticed that it sounds better, more "crispy" when the engine is cold, like first start in the morning. The backfire is also more often then. When I ride and the bike gets warm the sound gets a bit more gentle and not so "crispy" anymore.
Did any of U noticed such a thing too? Why is it so?

 

[vr46fan]

I have noticed the difference in sound between cold and warm. I can't say I've noticed any more backfiring though.

 

[Marcin]

I believe the backfire is more often and easier to get on cold engine because of the engine running rich and on higher rpms until getting proper temperature.

 

[FinalImpact]

^^ in addition to the fuel (from being cold/running richer= more fuel), the idle air control valve (IACV) is also allowing more air into the engine (to raise rpm when cold), so these two items coupled together allow more air and fuel which then reburns in the exhaust causing pop / crackle sounds.

It also explains why when warm idle settings of 1000 to 1100 vs 1200 - 1350 don't pop and crackle as much as there is less air introduced for reburn. It doesn't take much. Mind you pinhole leaks in the exhaust can throw lean codes on modern cars so that tiny amount matters!