hello,
My 93 warrior runs fine if you ride it for a short time like 30 minutes or less. But then after that time it stalls and when at idle and will not restart unless cooled down. Checked the spark and it was excellent.
Any suggestions on what to check next.

thanks

 

Your pitson rings are shot. The piston is explanding and not allowing for enough compression.

You may need to bore your cylinder, or maybe just a hone with a new piston and rings.

 

Check your compression to verify the piston/valves are sealing correctly, I doubt that is the problem,or it would run bad most of the time or blow smoke when you start it. How is your plug? when it runs bad,pull it to see if you are flooding or possibly vapor locking from heat. Let us know what you find, and I'm sure someone will have the answer for you, try to give us as much info as possible.