416 Jetting !HELP!

[JP400ex]

Im located right on the ohio/michigan line and its pretty cold here. I have a 416ex w/ 10:1 weisco piston, WebCam, race ported, UNI air filter w/ box cover off, and FMF titanium 4 Pipe and silencer. Im running the fmf with the silent core and spark arrestor. The guy i got it from had a 200 kehin main jet in it and the stock pilot and it was hesitating real bad when i would nail the throttle. So i put it down to a 185 and it still does it a little but not much. When i drop it down to a 175 it pops a whole bunch when i hit the throttle and let off, kind of like a bunch of backfires. So i am assuming the 175 is to lean (i know everybody says to only go with 165 or so)

I just cant seem to get this thing dialed in right, I want to be able to pop the clutch and nail the gas and have it take off with out sounding like its hesitating but everytime i lower the jet size beyond the 185 it pops to much.

[cals400ex]

i would put in a 42 or 45 pilot jet first. also, i assume your using the stock needle. i would also move the clip to the 4th position and then see how it runs. the popping may be because your lean on the pilot and needle. you could then tune in your mainjet.