problems with chain hopping on cassette.
Ok so I'm leaning towards the frame being bent on a friends bicycle that i have been working on for a while. So last year around this time he brought it over to me, and it had some indexing issues. Well i noticed the cassette had been pretty worn to a point. So i replaced the cassette and chain. I still had this indexing problem where it would just sit on the 2nd smallest or 3rd smallest chain ring, and hop up and down when trying to get to the next chainring. I have tried a variety of cable barrel adjustments and nothing seems to work. If i fix it for one chain ring it goes to the next one. I also bought a replacement deraileur and aligned the deraileur hanger. the only thing i can think is that the frame is bent. Does anyone have any possible suggestions?