Motorcycle Repair: Backfired and quit, mallory ignition, plug cable

Question
Hi Mike,
  I have an 86 Heritage (one of the first) with Mallory ignition
and a Mikuini carb. About two weeks ago I was driving home and
all of the lights went out, although the bike contuined to run
fine. Using the light switch didn't do anything, but two days
later, when I started it up, the lights came on and have worked
without a problem since.

   It's been running fine, with slight backfires (not loud at all)
when decelerating. However, today I was leaving my house and
got about 200 yards away, and the bike backfired twice, very
loud, from the exhaust, and immediately stopped running, and
won't start. Later, after trying to start it again (it wouldn't catch
at all) it backfired when I turned off the ignition.

   I'm getting gas to the carb, so I think it is an electrical
problem. How can I find out if it's a getting a spark (I have a
cheap multimeter), and if not, how would you suggest I try to
resolve the problem?

Answer
You can check for spark by removeing the plugs. Hook one up to the plug cable and while holding the sparkplug tot he cylinder turnt he bike over. You will see if its sparking.
Your problem though sounds like a short.So what your going to have to do is start looking for a bar wire or a bad plug in the system.
Good luck and happy riding
Mike