black smoke, black plugs, less average (7km/ltr) locally, checked spark leads with Multimeter, changed spark plugs,, throwing Kacha Smoke ( itching smell, eye burning), remade buterfly and mechanics said its OK (butterfly), changed all Carb kit, installed lower jet of 90, heigher is of 110 but i closed that,( secondary throtal (butterfly0 is locked after closing the main jet so it should not take air from there), Air flow mixture is fully closed, changed float valve settings several times ( checked every possibility),, in short.... i adopt every measure, but total waste of money...