yeah, my kx when i first got it had about a quart of oil in the bottom of the crankcase. at first i didn't know this. but after kicking the bike to try and fire it up for the first time to always find the plug completely fouled gave me a hint. (i was running like 40:1, so i knew it could be that fouled) so i flipped the bike upside down to drain all the oil. (about 1 quart!) and it helped soo much.
all the oil was from every time i kicked it the gas would fire but the oil wouldn't burn b/c the motor wasn't running. so after 1000 kicks the oil just built up. :bang: