kfx 50

just picked up a 2004 kfx 40 for my kids. its been running great,but today it kept boging down under power. i cleaned the plug and was going to check the air filter. there is no air filter. I'm not sure if it fell off or didnr have one in the first place. can someone show me a pic of the filter? mine looked like a cone off the carb, but doesnt look like a filter will fit on it.. could that be my problem??thanks

I'd clean the carb.

we use these on all the minis http://www.rectires.com/uni-pod-filters/

usually the 2"x4" or 2x6