I'd reckon a good candidate for non start with good spark is clogged start enriching jets (they are in the float bowls). To test for this buy an aerosol can of starting fluid (in Australia "Start Ya Bastard" outsells all other brands in spite of the contents being identical and a slightly higher price, buggered if I know why :-).
Anyway, see f you can get it running on starter fluid and if you come back several times during the course of the day and it starts fine, but will not start the next day, book yourself in for a carb refresh, but clean those pesky starting jets first and see what happens. BTW, contrary to any other jet you might handle, you do not need to be too gentle with these, they do after all only come into play when the choke ;ever is operated - clean them with oxy set jet files. If your bike sudden;y starts properly, order a complete carb rebuild kit and have at it.