Please Help! Honda XR 250L Stalling Out When Hot

I have a 1995 Honda XR 250L enduro that is a great running bike, but for some reason when it has been running for longer than 20 minutes and I come to a stop, it will stall out. It doesn't always do this, but every now and then it will. I usually wont be able to restart it until about 10-15 minutes later when it has cooled down a little. The bike never stalls out when it is cold or has been running for a short peroid of time, only when running for a while. Does anyone have an idea what could be the issue?

I will do a valve check! Could it also maybe be a bad coil?

So I have checked the valves and the clearance is right where it should be. I also checked to see if maybe it could be a bad coil, but I'm still getting spark when the won't start. Does anyone else have any idea what could be causing my bike to stall out or not start when it has been running for a while?