My car has always had this odd sound during warm-up. It seems slightly worse in colder weather. The sound doesn't happen immediately after starting, but maybe 30 seconds later these noises start, and they go away after a minute or two. Any ideas? It's an 09 R3.

Video link

 

Sounds like secondary air pump bearings. The only odd thing is the air pump starts as soon as you start the car, so it's a bit weird for the noise to come in later.

Suggest opening the hood and trying to locate more precisely where the sound is coming from.

 

Air pump power is the large-ish 2-prong(?) connector on top of it right? I did unplug that and it didn't make any difference. Really hard to pinpoint where the sound is coming from

 

does kind of sound like the secondary air pump.
it'll only happen when the car is completely cold, sometimes that means letting it sit overnight.

pic of what you unplugged?

 

Disconnected the large power connector to the air pump again and also the solenoid valve, so definitely not the air pump. I think i've narrowed it down to an accessory pulley. No sounds when running briefly with both belts removed. Alt and water pump feel OK by hand but the idler seems a bit crunchy. Going to go try pull the idler out now. There's no damn room for large hands down there!

 

HAH yup just got the idler pulley out, it's like 95% seized. I can barely turn it by hand.

 

nice trouble shooting and happy to hear you seem to have found the culprit.