I kind of agree with 3speed, it looks like maybe early '80s possibly very late '70s but the over the BB cable routing sort of rules that out. I also agree with it being a low end model. The rear derailleur certainly post dates the rest of the frame and components by at least a decade.
What country is that in?
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk