I decided to try out the EX500 carbs on my bike. The carbs I got were off of an '04 EX500. They had 35 pilots, 130 mains and N36N needles. I had enough sticky throttle issues with the PWKs to last a lifetime so I wanted to take advantage of the push-pull throttle. I got a used throttle and cables from an '05 CRF250. I also bought a new set of UNI filters since my old ones wouldn't fit the new carbs. All that came out to about $100 then I spent another $100 on jets.
Installation was just as easy as the others described. Grind a notch in the bracket to clear the backbone, then slide them into the BS34 carb holders. The CRF250 cables aren't a perfect fit to these carbs. With the adjusters all the way out, there is more freeplay than I care for. I'll go back and shorten the cables when I get a chance.
Based on what others have written, I started with 38 pilots, 142 mains, and two shims under the needles. It started right up, idles well and runs beautifully down the road. WOT feels really good but if I pin it while cruising there is a little hesitation as the RPMs climb. All-in-all, I am blown away at how well these carbs work with so little effort put into them.
Thank you ippytattoo and others for sharing your experience with these carbs.