Well, when failure accompanies recent work like this, it's usually a safe assumption to start looking at the work that was recently done.
First step will be to recharge your battery. These bikes won't fire well on a weak battery.
If you were inside the headlight bucket, I'd go back in there and check to make sure that you didn't dislodge anything.
A more methodical approach would be to diagnose from scratch, your engine needs fuel, compression, and spark. Compression is unlikely to be the problem here, and between the remaining two, spark is easiest to check for. So, pull spark plug #1, then hook it back to the spark plug wire and ground the plug's body against the engine. Crank the engine and look for a spark at the plug. Have spark = probably a fuel problem. No spark = keep looking for an electrical problem.
mystic_1