I had a lot of experimenting with mine. is it the stock or procycle needle? I think there's a rcommended ktm? one, and you can also chuck a stock one in a drill and custom grind it. Mine had an aftermarket exhaust. cold air will make it more lean than usual, changing non-riing day temps will make tuning more of a hassle.
http://drriders.com/bst-magic-stock-carb-mods-dr650-derestriction-inst-t16700.html
http://drriders.com/ktm-needle-mod-t14893.html