Hi everyone,need help tuning carb n2 on RH has yellow flame on Gunson with mixture screw closed and when adjusted open backfires on left exhaust,fuel igniting obviously.num 2 plug is black,sooty but dry,have set floats at 23mm with vernier and float guage,thought may have been the problem,will do another visual using clear hoses on w,end,I think Eddie may have had this problem a while ago,how did you fix Eddie?any help appreciated guys,Mark.