@RT325, me not having worked on one of these Yam's for a long time, as you say about the flywheel cam, do most of these engines have the fixed flywheel cam ? (I am most interested in the DT 125 air cooled)

I'm in NZ so we likely got different variations here & in Australia compared to the rest of the world.
But as a general rule of thumb, all electric start 125's have an advancer.
No flywheel magneto 125's have an advancer.
Some 175's from "74 to 'not not sure when', but not far after "74--had an advancer in the flywheel.