Ohh. The manual just said they should start opening at 1.8 btdc and the maximum ignition point gap 0.3 to0.4mm.I didn't see how to set the timing

www.manualslib.com/manual/1516213/Yamaha...nt&selected=4#manual they don't say how to set them. But i have a plan
mark the flywheel and some other guide to indicate 1.8mm b.t.d.c
1st- measure the ohlm reading with the points fully closed
2nd- adjust the point until i get a tiny bit more ohmls at that mark

Would this work?

Forget about the gap.  Ignore the gap.  You set when the points open by adjusting the gap.  If you "adjust" the gap after that, you completely screw up the timing.

You need to get the points to just open at 1.8mm BTDC.  That's it. 

1.8mm BTDC is found by rotating the flywheel clockwise after you find TDC.  And yes, you really need a meter to tell when the points just start to open. 

Oh, and I'm saying 1.8mm because that's what you've said.  I don't have the timing spec for a DT50.

Sounds like a pretty reasonable plan.
Whatever way you go they must start to open at 1.8.
That's about all you need worry about.
Don't get 'too' sidetracked on trying to get gap plus timing perfect.
Timing is the important one.
Well--unless there something very wrong with the points like the fiber heal is damaged or the points button has dropped off.
Had that happen once haha on a battery ignition motor Fugi heavy industries Victa 50cc scooter 12 volt & points were like an arc welder which made me realise those points buttons are made of something very special.

The timing is for a gt80 and mx80 but everyone that sells the manual says its also for a gt50
i.ebayimg.com/images/g/o9UAAOSwd6FilpzK/s-l1200.webp

They all run 1.8mm btdc & points ignition is much the same on all those models.
Can't go wrong.

Well tried again and again to make them open at 1.8mm but they always no matter how i configure it start opening after 1.8mm, if i try to make them open sooner the gap is huge and they won't fully close. I'm at a lost seen guides here and yt videos nothing realy helps

The magneto is from a pw80 so maybe the cam is different o.o but they look the same

I'm wondering if you might be trying to set ATDC accidentally (happens to me sometimes) and/or are rotating the engine the wrong way?  These systems don't have much adjustment range so from what you're saying there might be something mechanically wrong in the ignition system (kind of unlikely unless parts were recently changed) or simply a misunderstanding of the process?

Points could possibly be wrong/damaged or crank key bad?

If points and key are good... at this point I'd try setting the maximum point gap at about 0.014" and see how it runs.  Timing should be pretty close at that maximum point gap.  (If it runs good, thank RT325)