2003 honda xr100r dies when warm

[toolbox902]

hello all
i am hoping yall can help me out.. my 03 honda xr100 starts first kick with choke. then i let it warm for about 30 seconds the turn choke off. ok then i start riding and it running good but after about 3 minutes it bogs down and sputters and backfires and dies out. next morning same thing. i just cleaned carb and still same thing. anyone have any ideas what could be wrong? thanks in advanced

 

[dirt bike dave]

Check your valve clearances. The clearances tighten up with wear and get even tighter with heat. They are probably way too tight. When the motor gets hot, the valves are not closing all the way. Valves not closing all the way = No compression = stalling and back firing.

 

[toolbox902]

ok thanks i will try that today

 

[toolbox902]

ok well the valave closer too the carb was indeed too tight. also there was a ground loose by the coil. i loosened the valve to .002 and tighten up that ground and that got it going! thanks for the help! saved me a shop visit