My buddy has a aftermarket header and pipe on his 350x, and we used I think a 142 or so on it. You shouldn't be way off, but it all varies according to where you're at, time of year and alot of other factors. Try taking off the airbox lid for a little while, changing to a new sparkplug and ride it around the house or something just to see if that helps it clear out. Also check what position the clip on the needle is in. If this fixes it then I would step down to a size smaller jet, if not then you may have something plugged up in the carb or other issue.
73 cr250m elsinore, 85 atc70, 85 250r flattracker, 87 250es bigred, 86 tecate, 2004 gas gas de300