[choneofakind]

Check out this thread for help on cleaning. There should be pictures up somewhere in the thread, just not in the first post since Kelly left a while back:
http://www.ninjette.org/forums/showthread.php?t=65198

faq.ninja250.org also mentioned soaking them in pine sol:
http://faq.ninja250.org/wiki/Cleaning_the_carbs_1

Buy a couple bottles of Pine-Sol and mix up 3 parts Pine-Sol to one part water. Pine-Sol doesn't hurt rubber/plastic, so you can leave all the hoses and plastic pipes on the carbs. This will make the hoses more pliable, and you can do the same with the intake manifold boots as well.

You do need to remove and not soak the slides. The slides and diaphragms are all one piece on the 250 carbs. So, remove the 4 screws holding each black top cover, pull those covers, the springs, and then the slides.

To get the most benefit from soaking, the float bowls, floats, fuel needles, needle seats, jets, and emulsion tubes (the, uh, tube that the main jet screws into) should come out as well. Soak the jets and everything else you removed, except for the slides and diaphragms. You should also work the choke a few times while submerged to get the Pine-Sol everywhere.

Find a BIG container/bucket and some sort of fine wire rack or mesh sieve (like ones for a BBQ grill) that fits inside. The mesh will let all the yucky stuff that falls off settle on the bottom, and you won't have to fish around in the murky fluid looking for one washer or small bolt/screw. Pour enough of the Pine-Sol solution into the bucket to cover the carbs.

Soak the carbs and parts for about four days. Scrub the open areas just a bit with a toothbrush and green scrubby. Then do a normal carb cleaning for the jets and interior passages of the carbs.

The carbs shown at the top of this section, from a bike that had sat outside so long there were chunks of dry-rotted tread falling off the tires, now look like this, and the bike starts and runs well, without a lot of hard work.