1969 dt250 been posting alot about
red mark on flywheel can you set timing from it?
or do i need a guage?  i have head with slanted plug hole so i gotta take head off.
can i just measure 3.2mm or think i should fork out dough for a digital guage with magnetic arm?
if you set your point gap shouldnt it be near time from setting the gap?  
i just installed new points and went back too old coil and got spark so im celebrating getting spark back.  dont know if it was worn points slider pad or me.  probally me but now i have spark back!

Not sure the mark was colored originaly but maybe, good idea too. So the notch in the flywheel window?, if the tab is at right angles that comes of one of the coils then in a perfect world that should be 3.2. Those tabs get bent over 55+ years but it's a pain to need to pull the head. I just mark something like a nail at 3.2 held vertical down the angled hole. Touching top one side & bottom of the thread on the other side of the plug hole is pretty much vertical. Points breaking at that point. i'd do 'that' & see how close it is to the tab aligning to the notch. All done by points gap but i'm sure you know that. Ps, could then strobe it although that can keep you awake at night as they never seem to hold perfect. Not sure why--main bearing wear, points pivot wear & play. Best not top know sometimes. They're a forgiving old motors those first ones if things aren't perfect. I'd better add--that's only how i do things & sometimes i'm as rough as a bears bum, but i know what works for me.