The dual-intake system consists of two intakes. The primary intake supplies richer air-fuel mixture through a carburettor. The secondary intake supplies air alone to the top of transfer ports through reed-valves.For engine modifications developmental testing was undertaken to establish desirable flow rates through each of the intakes, and achieve desirable air-fuel mixture. The performance of modified engine and the two wheeler for reductions in hydrocarbon emissions and specific fuel consumption was taken on engine test bench and on a chassis dynamometer.The results showed about 34% reductions in hydrocarbons mass emissions accompained with about 28% reduction in fuel consumption. The reduction in carbonmonoxide emissions were substantial whereas the carbondioxide emissions reductions were marginal.