[QUOTE=Sheldon Brown]Looks to me like most likely 1983-84, maybe a year either way.
No way it has a cassette hub, BTW.
See also:
http://sheldonbrown.com/japan
Sheldon "Good Find" Brown
QUOTE]
Indeed, if it is anything like mine, it has a shimano freewheel with those slightly twisted teeth (Uniglide?). But mine was skipping. So I just picked up a new chain and thread-on freewheel.
As for narrowing it down, I read elsewhere that the second digit of a Miyata serial No. may indicate year of manufacture.
I post pics of mine to compare to the yellow one.
Sheldon, if you're still monitoring this thread, could you explain to me the significance of the Miyata Radial tires you mention in your article? I had originally planned on "upgrading" to Conti Ultra Sports (100 psi range).