Hi. Another newbie here. Also have a ybr125. And it has an intermittent squeak/squeal, a rotating sound kind. I have ruled out the chain, as when it finally stopped raining not so long after I picked it up, I gave it a thorough treading, and even with that every now and then it comes back. Tried the wheel spin / wiggle to test the bearings and they seem fine, and checked out the disc, no scoring so nothing trapped and its not the rear drum as it still makes the noise with the brakes applied. Not sure what it is as it only occurs every now and then. If I come across what it is, ill let you all know.