My 2002 yz 250 began stalling the last time riding. It was the end of the day and I thought a plug had fouled. The next time riding, I replaced the plug and started the engine. It ran a few minutes and then shut off. Kick started it a few dozen times and it would start and then die. Much like the kill button had been pushed. I removed the tank and checked all the wire connects and the coil ground, but no change. Has anybody had similar problem?