Son-in-law sent me this link and asked me what I thought.
Honestly have no idea. Too little info. 1980 Harley
Do not know if there may be a common problem with them that causes the problem..... :dunno
could be running too rich and worn plugs I would change them and readjust the Carb. A weak battery with not a lot of juice or a bad stator can short out under heat conditions lessening current for spark for the coils may be a possibility as well.
Too much money, and it has a lot of mismatched parts; wide glide forks, rear fender & seat don't align, forward shifter looks wonky, rubber sleeves on forks? I'd be afraid that every time it needed work, you would have to research what year/model part you'd need. There's nice Evo Sportsters for that money. JMO