Your best bet might be to talk to some one from Sudco, www.sudco.com , they sell a line of brass needles at $5 each rather than the exaggerated factory price. They are a whole saler but will likely be able to give you the names of some distributors. My first pick would be RD Designs. You can track them down at www.rbdesigns.com From my experience and others on this board I'd suggest you pick up a 5 or 6 needles including a
CEJ, CEK, CEL, BEL, BEM and BGL etc. or ask Ron for some recommendations, he's been pooling a lot of info for KDX owners with RB Designs modified carbs. For the most part the needle selections should be transferable to KDXs running non-modified carbs. You might also check around Japan for someone selling jet needles for Keihin carbs. You don't have to buy a needle from Kawasaki to find an appropriate profile for your KDX.
Hope that helps,
David