Can someone please remind me which way the air screws go on a though to lean off a touch, carbs are ivanised but after standing I've just blown the passages and jets through to cure a misfire but still got a tiny splutter just at pulling away speed, carbs are balanced and idles lovely I think it's just a touch rich.Currently 4 turns out but note ivanising instructions recommend 4.5-5 turns out, is that leaner or richer? Must find a small child to get their hands in to adjust and try.Otherwise runs superbly and pulls like a train all the way to "a tad over 70 officer".