I’ve rebuilt my Spark with XTR Di2 1x with a Sram XX1 10-42t cassette, Sram XX1 chain and Eagle chainset.

It is very noisy/notchy as though the jockey wheel is hitting the cassette type of noise, not indexing noise. I’ve read running the XTR mech with a Sram cassette is fine and works well, should I have used a Shimano chain maybe? I assume there’s no issue keeping the Eagle ring even with an 11s chain?

Any ideas before I just start messing/swapping random components.

Every gear or just some?

Easy to check if the guide jockey or jockey cage is fouling the cassette as it’s just a visual check whilst slowly turning the cranks.

Err, have you threaded the chain through the jockey cage correctly? That sounds horrible in every gear. Not that I’d know from personal experience you understand, just something I’ve been told about 😓

Every gear, The jockey is 100% nowhere near the cassette, yes threaded correctly.

Is the chain running smoothly on to the lower jockey wheel? I set up a 1x recently and the chain wasnt meshing well with the lower jockey (xt mech) and jumping off sideways. Fixed it by fitting an upper guide pulley in the lower position. The longer teeth seem to grab the chain much better.

No, I think that’s the issue but never seen it before, the chain links seem not to be feeding onto the lower pulley, don’t understand why really though.

Me neither but suspect it’s partly the new chain. Try a longer tooth pulley, hopefully will do the trick

Worn chainring with a new chain maybe?

I used one of these (left) but there might be an ultegra DA level one

https://www.merlincycles.com/shimano-105-5800-11-speed-jockey-wheel-set-103056.html?source=PHG

It’s all brand new components.

Thanks Joemmo. I might give that a whirl.