yamaha surges at idle

i have a 2000 yamaha ttr125l, when the engine is warm the idle surges
high a idle about every 15 seconds for about 5 seconds

ive tried all the usual things ...any thoughts would help
thanks

well, it could be many things....

Is it smoking as well?

check for any air leaks in the intake (cracked carb boot, carb not in quite right.... things like that).... check for a blown crank seal on the stator side (remove the cover and look for leaking signs)...

If that fails to produce results, check the carb itself (take it apart and clean it out)