if your this lost you might want to just take it to a shop. just make sure the shop KNOWS yfz's and will stand behind their work and make sure you ask them specifically about that....
4 strokes are kinda tricky to get jetted just right they are more finiky than a 2 stroke. the carb supplies fuel based on the engines PULL on the carb so sometimes to get the right fuel air you need to lean it down.. ( on bigger builds) because the carb is getting much stronger pull through the carb and the carb is pressured up more.. 4 stroke carbs also need to atomize much better due to the ports curves and such and that curve likes to switchthe fuel back to non atomized. and in al reality you will end up between a 160-178 main, and anywhere from a 42-52 pilot it just takes time.
i found that on one i did the 170/50 quick shot 3 ( excellent!) worked killer and also doing the pumper link or mod or o-ring worked killer as well. it seemed to me with the quick shot and adjustable leek jet it liked a much bigger slow jet. they all seem to jet a lil differnt and you will really need to know what feels right and or check plugs to get it really close a dyno with a "sniffer" is almost ideal but most bikes i have seen come off the dyno are lean because of the load, airflow, time and hp gaisn that most dyno tunners are looking for. i k now the quick shot 3 seems exspensive ( 100 bucks) but its a very nice addition to tuning and will take the BOOGOGOGOGG out of it once you get it right and as soon as you stab the throttle it jumps into a wheelie instead of BOGOGOGOGO you will be very happy