I have a 2004 sportsman 500 atp that will run only if you pull start it. If you use the starter in any way it has no spark.

 

check the battery voltage to see what it is before you crank it and while your cranking it. chances are maybe theres not enough voltage.

 

the pickup coil (pulse coil) is too far away from the flywheel. starter cant spin it fast enough to excite this coil. pull start will let it excite. pull the recoil housing and check the gap. if it is within spec but still doesnt work you can pull it and elongate the two screw holes to get it closer to the flywheel. should fire right up.