I have a 2005 yfz450. You can ride it for 10-15 minutes and then it dies. Before it dies it backfires and acts like it runs out of gas. I have changed the plug, CDI box and carburetor worked on. This started after having issues with it not wanting to idle very well, but would run great. Any ideas

 

Checked valve clearance,plus compression?

 

Plugged fuel cap vent?
Coil getting hot?
When it dies check for spark at the plug and fuel in the carb.
If they are both good check your compression.

 

Gas flows freely to carb and if you let it sit for a minute or two it starts right back up

 

Sounds like something in the ignition system is overheating. I would also suggest checking for spark next time it dies