Just for future use - get a can of starting fluid at the auto parts store. The next time it is a recalcitrant starter, spritz some of that stuff into the throttle body ( put rubber crossover hose bock on! ) - and try start again. This stuff likes to combine with oxygen like crazy, and will tell you tout de suite that you have spark, compression, and fuel and timing ( from the can anyway ), and ought lead you to more efficient troubleshooting.
1982 Spider Veloce
1999 BMW R1100S