I installed the malossi kit, proma pipe, running on 81 jet with stock carb. mixture is 50:1 so I cannot figure out why I am still four stroking at WOT. most times when I back off the throttle a bit, it still four strokes. where should I look first? any suggestions? sometimes it will be fine and crank wide open and fly, others it will 4stroke. help! it also will not idle. I'm going to take the carb off and clean today, think that could be it?