I remember kicking mine for abt 100 times only to find out, I was kicking it on the exhaust stroke!
I then learned to listen for that little click when the valves hit TDC..then a good kick and it lights..but as Luke says, check to make sure you got spark first, and that means spark at the plug you have in the XR..you can have spark with another plug and the plug in the bike be a dead one..good luck