Yes, what year is bike? Any modifications?
I would replace the float needle valves, O-rings, set the float height, remove the idle mixture screw caps, so you can tune them, and bench synchronization.
If your in need of a full carburetor refurbishing head over to Ninjette.org, or EX-500.com and contact a user name Ducatiman. He has the proper tools, resources, and craftsmanship to do the carburetors so they are new again, if not better. Tell him Ghostt sent you.
From his post,
Custom Carb Service
I'm pleased to announce a formal, refined carb service program for our members. I wish to expand and offer varying levels of AFFORDABLE custom carb work you can TRUST... exclusively for the EX community, though certainly not limited to EX carbs. We all know how astronomical dealer prices are these days, not even mentioning the frustrating experiences dealing with them.
My basic carb REFURB SERVICE entails: full disassembly, split, pilot screw cap drilling, sodablasting, treat bodies in heated ultrasonic machine, verify passageways and circuits (pilot, main and choke) are clear , ALL new orings/ rail seals, float valves. Fuel levels setup, throttle plate synch, fully bench checked, ALL tested...not just "carb cleaning" but an actual TRUE REFURB .
also for you DIY folks...selling carb kits (including orings, float valves and stainless buttonhead screws) as a complete set to service 250 carbs available NOW and shipping daily.
Unfortunately I'm forced to limit this to US/mainland transactions at this time.
*i have dealer experience (10 years at a Yamaha/BMW dealership as a youngster in the 70's) where I became a bit familiar with carbs
Some examples of my work (though not necessarily 250)
Thanks for looking, reading. Please PM any questions/concerns/inquiries. Will be answered quickly.
If you are not inclined to do the carbs up correctly in *the first attempt*, lack equipment, tools or energy....please give me a try. Affordable, honest, quick service.
Here's some before and after pictures of his work
Keep in mind the owner of these said he had cleaned them numerous times, before sending them to Ducatiman, the before picture is the way he got them, after the so-called cleaning.
Below are after he's done.
I can personally vouch for him, I've known him a long time.
Depending on the age of the carburetors, a full refurbishing is in order. Also if it's been sitting awhile, or you just want piece of mind, his full service prices are extremely affordable.
I don't want to discourage you from a diy project, but as with any diy project you need proper tools, and keep in mind your dealing with gas, which is dangerous, and flammable.
If you have any questions please feel free to contact me.