The Design and Development of a Reliable Low Cost, Fuel Efficient, Low Emission, Family of 4 Stroke Powertrains for Scooters and Mopeds

This paper describes the process utilized in the design and development of a 75 cc powertrain for two wheeled vehicles. The powertrain was designed for the optimum combination of fuel efficiency, reliability, performance and low initial cost. A new approach to the design of these powertrains was utilized, which included the use of a high pressure die cast aluminum cylinder head with high tumble ports, a single piece crankshaft with cracked two piece connecting rod and plain bearings on crank and camshafts. The process of design and development made extensive use of new analytic and experimental methods, which are described in this paper.