So, I received my replacement frame...let's just say I'm not exactly a happy camper
The rear threads for the rear brake caliper are all messed up and not even close to true as you can see in the following pictures. What can even be done for this??

I can't really tell from the pictures...but double check that the bearings are 45/45.

You can use something like this: http://www.jensonusa.com/!D2xBgoZtgZgI4LRKFRe5AQ!/FSA-Integrated-Crown-Race-Reducer?utm_source=FRGL&utm_medium=organic&gclid=CMmfhr6uiccCFVAkgQodECwHqw

and run the stock headset.

They are 45/45. This frame didn't include a stock Chinese headset but I do have a cheap FLYXII headset on the way. It's the typical ones that are usually included with these frames. Do you think the ridges and groves in the headtube cups are any concern? Especially considering the wear marks on the bearings?

Here is a video of the terrible sound. The recording kind of muffles it, but it's much more sharp and "cracking" sounding in person.

Did you grease the crown race before installing it?

Yeah, I used some bearing grease the first time around and last night I re-greased it with the silicon lube. No dice.

The only thing I see different in your setup vs everyone else's is the straight steer tube.  If you had a fork with a tapered steerer to try that would be where I'd start.  Possibly your crown race is not fitting properly into your lower bearing of your headset and is causing some movement.

Are you feeling any movement or just hearing a noise?

Not feeling any movement, it's nice and snug. As for the race, I ordered an adapter specifically for my headset that allows the Cane Creek Forty bottom to work with a straight steerer. Nice snug fit there as well.

I think for the time being I'm just going to ride it. I've put about 15 miles of rough single track on it and no real concerns yet. Time will tell I suppose.

What did you grease? I had identical noise as you describe in my first ride or two.  Some super sticky silicone based grease between the bearings and the frame stopped it instantly.

At first I greased just what you did. When it was all said and done, pretty much every square inch of the headset was lathered in it. I'll look into trying some sticky silicone based stuff next.

I just want to say, thanks for all the quick feedback and suggestions everyone!

What fork are you using?

2014 Reba RL Solo Air with 1 1/8th straight steerer tube. I bought the corresponding crown race from Cane Creek for putting a straight steerer in a tapered headset as well. Pretty positive it isn't the fork, it came off my previous hardtail and didn't have any noises when I rode it last week.

Hello,

I recently purchased and just finished building up a FLYXII FR-202. Everything went together really well except I seem to be having some noise issues and wondered if any of you had a similar experience or advice.

For my headset I went with a Cane Creek Forty IS42 top and 52 bottom. The problem arises when I brake hard with the front and occasionally when I pressure either side of the bars individually. I get multiple unsettling cracking sounds coming directly from the headset. I've tried the usual, greasing rituals and about every different combination of torque on the star nut but nothing seems to change it. I made sure it wasn't the bars, stem, or pesky internal cable routing.

The top bearing drops in fairly easy and doesn't have play and the bottom is snug, requiring a bit of force to press in but easily doable by hand. I'm thinking it might be something with the the top cup but I'm not sure, I've never worked with carbon integrated headsets. Is there any cleanup process required for these frames before installing the headset? I couldn't see any actual aluminum cups, it just looked like carbon roughly formed into cups? Is that correct?

Any advice or help would be greatly appreciated!
Thanks!