I am running a 975 kit on my King Cat and it is a little lean in the mid range with the stock 9DFH2-59s. Am trying some 9DFH2-58s, part number 6505-200. I don't know for sure if it is going to do what I am after yet though. The 58 and 59 numbers are supposed to measure diameter so my thinking was the smaller needle should be richer but have the same taper. Hope this helps
i just removed some 56's that came with mine. it was pig rich so i stuffed in some 59's and i know i'm going to be really lean in the mid so i think those 58's will work better, thanks.
next question, i know that the letters are the taper but what throttle position do they change. for ex. if i'm lean at 2/3's throttle do i want to change the first or the second letter?