Originally Posted by
shnibop
Michael Angelo- it's a 6/7/8 speed chain. I have a wider chain (a Regina) on there previously and the problem was worse.
Homebrew01- yeah,
the inside plate of the derailleur is contacting the limit screw stopper area.
Ex pres- I will measure chain line when I get home from work. How do you do that?

Nothing a little Dremel action won't fix !

Skim .020" off the inside plate of the derailleur and you'll be good to go.