A few days ago i took my yz250 down to a track and after a couple of laps it started to feel boggy and choked up so i came off the track and after 10-15 min i tried to start it again and it wouldn't start ???   i got the bike home and have taken appart the carb blown it out with air and cleaned it checked the spark and thats good and i have tried using a heavy fuel to oil mix to encourage it to start but the most i have got out of it is 30 seconds of boggy running. The only thing which gets hot is the kickstart   lol    any ideas?

could it be flooded? is the sparkplug wet?

the spark plug does get wet i take it out after every couple of mins and dry it though 

chances are the engine is flooded, take the plug out and leave it out overnight, any excess fuel will evaporate off. Then try again with a new sparkplug...that's what I'd suggest

thanks i will try it