My 2002 sportster 1200 runs for 30 sec. then dies , loses spark , turn ign. switch off and back on it will start and run for 10-15 sec. then lose spark again. any ideas ?

Duplicate question already answered

It sounds more like a fuel problem to me then a bad coil or spark ign the spark should be blue but its hard to see in daylight
You say you rebuilt the carb are you sure your main mixture jets are at least 2 to 3 turns out off the stops .
Try pouring fuel down the barrel fill the float bowl if it runs then dies its fuel don't let it catch unfire you should have 45 sec. of run time then adjust the the mixture screws 2 turns is base but when its is running good turn them in 1 at a time and give it 30 sec. to adjust until it starts to stumble then back it out a 1/4 two 1/2 turn then repeat on bank 2

It looks like your gas pump is out (or gas pipe is clogged).

It could be something as simple as a corroded connection in the ignition that intermittently turns the bike off. That is a heck of a wiring gremlin though. Another possibility is that it isn't spark at all but some weird intermittant clog in fuel delivery, like a stuck fuel filter...

bad plugs, bad plug wires, bad gas

Alternator's shot. You're probably running on battery only till it drains down.

A bad battery does this. I'd take the battery out of the bike and take it to an automotive parts store. Ask them to "load test" the battery. More than likely, this is the problem.

However, when you connect the battery back up, connect the positive side first. Make sure the switch and everything else is OFF. When you go to connect the negative battery cable, see if you notice a spark. If your bike has a computer onboard to run fuel injection, you see a small spark but it'll be a very small one. If you get a large spark, you do indeed have something pulling a lot of current when it's not supposed to.

Good Luck
Steve

the running and headlight are on different terminals of the main light switch,so either the switch has lost power ,=fuse,plug and socket loose or adrift, or in the switch the rotary plate which bridges the contacts as its rotated is broken or adrift, cant be sure but dosnt the ign switch energise the light, the wiring diagram would show if it is or not