I'm glad I noticed this thread before starting a new one. :>
I just got a Nishiki "custom sport", which (from descriptions on this forum), I'm thinking may be one of the 70s "gas pipe boat anchor" type clunkers. My gf just got an 80s (guessing here [ok - she says actually probably early 70s) Japanese bike (a Zebrekenko), which feels significantly lighter and rides really well. The guy who sold it pointed out that the bike would be lighter with most of the components taken off, but it's still pretty heavy. I can lift it with one hand, and it's still lighter than my Bianchi Milano, but it's definitely on the heavy side. The frame is in pretty good shape; not really any rust and not too many dings / scratches. There's a license renewal sticker from '81 on it, but based on pictures and descriptions, I'm guessing it's a 70s model.
looks somewhat like this, only with maroon paint:
http://pittsburgh.craigslist.org/spo/336549139.html
It does have the stem shifters, safety levers on the brake levers, possibly the metal disk in the wheel; don't believe the crank is one-piece at least.
I'm planning on replacing both wheels, and removing the rear brake, etc., and will possibly replace the crankset etc. later. I guess if it's still too heavy, I could find another frame later and move over the components... but am I going to regret this? Should I cut my losses and try to sell the frame and parts? Or will I be happy to have a slightly heavier frame for riding around town?
I can take a picture later if folks want.