I have 28mm pwk's & as far as a baseline to start out with for a stock motor with fatties: 155 mains. If I was you I would start out with 165 & work your way down a bit For the most part keihn goes in increments of 2 or 3 for the most part 155,158 160,162,165. I currently have some mild port work, shaved head & fatties & I'm running dual 28mm carbs with 175 mains. I'm not sure about the needles except they were changed out to a diff type by the store I purchased them from to accomadate the banshee. By the way 175 Keihn jet is equal to a 330 stock carb jet (mikuni). Hope that helps.