had the Yosh and new jettiung for about 4 months now. all is good but just in the last 3 rides. i hear more poping when I accererate and then back off on the throtlle quickly... like up I power 3/4 throttle up a short hill and oh here comes a qucik down hill rut, so i back off the throttle quickly and pop pop two back fire.. thats when it happens. whats up with that. poping is lean right? it worked good for 4 months --- hmmmmm crab geting soiled??? naw how baout fuel screw needs a 1/4 turn to richen it up?? if so which way adds more fuel. clockwise?