I know, I know, its almost impossible to name a mystery frame without a plethora of clues. But this (80's-90's) japanese frame (got that so far) has one distinctive feature I've never seen on any frame...the tubing used for the chainstay bridge is only 5/16"in diameter...no bigger than a pencil.
Anyone recall seeing a japanese frame with a pencil chainstay bridge? Frame is light with nice build quality, has scalloped seatstay endcaps if that helps but that's not uncommon.
Jack Romans
Sacramento, Calif