My 1985 Suzuki LT185 wont fire the spark plug?

I can't get my lt185 to fire the spark plug. The plug is good. It fires in other 4 wheelers just fine. I have all the switches and choke on the right position, and im not worried about fuel or anything just what can make the plug not fire. It is a pull cable start also. I was just wanting to know if anyone had any idea about whats wrong?