When on either of the top two cogs , very very noisy, any reason?
B-screw set correctly? Clutch tension adjusted back a little?
I've had this in the past when the clutch was binding a little - is it better with the clutch disengaged?
KMC Chain maybe? Ive found them much noisier than the other options on 11 spd.
I’ll try without clutch , just changed the chain only had on a £11 Sram but made no difference
Adjust your chainline in as much as you can?
just changed the chain
Do you spend much time in those gears, if so is it a worn cassette and the new chain isn't marrying properly just yet?
New chainring?
I've just gone 1x11 (from 1x10) and notice fine noise from the narrow wide chainring when on the largest cog. I'm expecting it to reduce as it wears a bit.
Oddly doesn't seem to do it on the other end even though the chainline is 2mm more inboard than it was on the old setup.
By top, do you mean biggest? If so, and it's not the jockey wheels touching the sprocket (b-screw adjustment) then it's probably the just crap "standard" chainline for 1x11. See https://singletrackmag.com/forum/topic/sorting-xt-m8000-chainline-an-over-engineered-solution/ . Adjusting the chainline certainly helps, although it may improve a bit over time anyway.
Oddly doesn’t seem to do it on the other end even though the chainline is 2mm more inboard than it was on the old setup.
It's probably still someway outboard of the middle of the cassette, and 1x11 adds the extra sprocket inboard of where it is on 1x10.
