No spark

[steadyroller]

My son was coming home from work today and got about ,5 miles from the house and his bike died, and would not start back. After checking that there was gas going into the carb, we removed the plug and checked it with my lawn mower and it fired good. We put everything back together and it still wouldn't start. I then suggest we do what I should have done earlier; remove the plug and check to see if it is getting fire. Bingo. The plug isn't firing. Any suggestions? I'm not much on a 2-cycle engine, esp a motorcycle. Thanks