Noisy Chain - with vids

So I've just finished up a new build https://www.lfgss.com/conversations/302299 and am having problems with a noisy chain.

I measured front chainline and calculated the back from Sheldon's data and think it shouldn't be more than 0.5mm out (of course my measurements may be less than perfect).

Vids of funky noise:

1: https://youtu.be/g8OuTUlgm4A
Filmed from side. This video makes the noise sound louder than it is really, but will give you a good idea of it. (p.s those are not my pink trousers).

2: https://youtu.be/1UH3vfTY4qA
Filmed from the back of the bike. In the slow-mo section you can see that sometimes the chain looks a bit "S" shaped (see 00:22) and other times it looks okay. You can see it most obviously if you just skip through the video while paused.

When looking from above the chain seems to flick left and right a little, seemingly randomly rather than systematically.

I did buy the chainring 2nd hand off eBay, so do have the one that came with the (new) crankset - could try that but would rather not.

I've tried the chain tight as the proverbial anoos, and loosey-goosey. Maybe a little quieter when loose but not sure if in my head.

Unlikely to be chainline problem. Maybe requires lubrication. More likely to be that the sprockets and chain are not sufficiently intimate with each other. If they were all new, I'd say it would settle down as they start wear in the useful phase of their existence. If they are worn, then maybe they will settle down, or maybe not. Especially if the rear cog is very worn.

Are the rear sprocket and chain both new?

That chain looks quite tight. A little bit more slack might quieten things down and possibly reduce wear too.

Cheers for replies.

• Everything is new. The chainring is 2nd hand but, I gather, was hardly used.

• Loosening the chain off makes a tiny bit of difference, but nothing significant. It's not 'tight' right now

• I haven't lubed it beyond what came on it out the packet, simply to avoid getting it all over everything while pissing about with it. Of course I will do before riding.

Some new chains come in really thick gunky lube which makes them a bit sticky to start with. After the first few applications of normal lubricant they come right.

Worth knowing that some chains are just noisy! I have had a lot of success however with centreing my chainring a la sheldon method and using dry lube on a freshly cleaned and dry chain. I'm running surly cogs with Izumi chain and sugino chainring and everything is silent.

.

The chain came feeling fairly dry, so not sure it's that.

The chainring centering looks like way too much effort for me right now. I'll ride it for a bit and see if it settles down.

I swapped to the cog on the other side and the same noise, so at least I can rule that out I guess.

Some chains and rings are just noisy as has been said. One of my fixed gear bike makes a racket, particularly when I'm slowing, and my other one is as quiet as the grave. I just pout it down to the chain and sprocket combo.