Hello,
Here's a frame that purportedly is late 70's Japanese. I'd really like to identify the make and model because it's got such a sweet ride.

It's too bad that it's in poor condition. Here's some facts that might help, and some photos below.
Thanks for any help, and sorry it's not completely a classic.
-- Serial number stamped on left side seat tube by BB shell
-- Serial number SOL 2016 or SQL 2016 (space between letters and numbers)
-- 27" wheels
-- I don't have the original fork