Sounds like the battery is causing the issue. I recommend Motobatt, Yuasa, Katana or SSB brands.
Battery or system voltage less than 9.5 while cranking means no spark. Will crank over quite fine but simply will not fire up.
This model should start and run within two revolutions, hot, cold, summer, winter, seaside, mountains, full moon or new moon. Any cranking beyond is a waste of battery, starter and time.