i have the same problem in the past few days. Only in the morning , engine turns but not starting , after the 3rd time it starts. I have recently changed spark plugs and gone from Golden lodge to Champion and i dont know if this one cause.
Another think that i have noticed though is that cruising under 2k rpms is that i have from time to time small "hickups" probably from missfires. Also if i am accelerating slowly , rev meter also has "hickups" up until 3krpm and i dont know if it is weak battery or again spark plugs.
So my next steps are to put back my old golden lodge spark plugs , check cables, clean negative connections and clean carb needles.
Sprint 1.7 '85