Originally Posted by
Pompiere
Yes, take off the cable stop, the downtube shifters don't need it. Did the bike originally have stem shifters? Also, the bike looks identical to the 310 that I have. Are you sure it is a 610?
Yes, it's a 1981 model 610. The prime difference to your 310 is the triple crankset. In this case, the inner chainring appears to have been removed, leaving the very close 52/47T combination. This is not a typical double combination for a Miyata of the era and in combination with the small bolt circle indicates it was originally a triple. Stem shifters would have been original equipment.