did you look down the middle of the jets to make sure they were cleaned out? you should be able to see a nice clear hole down the middle.
did you blow out the passage ways w/ compressed air? were you able to feel air passing through to the little exit holes in the carb throat area when you blew from the removed pilot jet passage??
http://faq.ninja250.org/wiki/How_do_...n_the_carbs%3F