The Ktm cylinders are pretty hardy these days. I’ve had scoring marks and honed em out put it back in and all went well. I have a hone if you need it but in melb west. Also use the wiseco pistons they are tighter tolerances but listen up more due to how they build them. I have used vortex wossner wiseco and found all to be good with no noticeable difference in how it ran. I have replaced cylinders with new and found the noises never went away due to ktm rattling clutches. Just slap one in it she will be all good if you need advice let me know via pm and I’ll ring you in need.