POP at start and now nothing

[pimpin]

I have an FZR 600 / 400 which I haven't riden for years. I tried to jump it with an old car battery the other day (not even connected to a car etc). the dash lights came on but as soon as I went to start it there was a pop which sounded like something shorted out but it came from the front end of the bike. I checked the fuses and nothing unusual there. Before I get the multi meter out and spend a crazy amount of time checking continuity I thought I would check here and see if anyone else had an idea what went pop. Thanx!