Motorcycle Repair: Yamaha Enduro, dt2, at1

Question
I recently got a bike with no paperwork.  it is a 70's vintage Yamaha enduro(?) (either 125 or 175?)
i am trying to figure out the year and size - the only thing legible is the number stamped onto the frame at the yoke - DT-1F-128208 / any help would be appreciated

Answer
Joe,

-the DT models were 250cc until 1974 when they
used "DT" on 125 and 175 etc.

-Up until then the 125 was an "AT1" and the
175 was a "CT1"

-your bike is likely about a 1972  DT2, which is
a 250cc unless someone has modified something.

-you could pull the head and measure
the cylinder bore to be sure:
a 250 is about 70mm across, 175=66mm, 125=56mm.