India is a country of 1.32 billion population with 221 million registered vehicles on the road. Of these, 933950 three wheelers entered service in the year 2015-16 (114% increase from 2005-06). With atmospheric pollution and emission norms in mind, it is essential that we bring down the emission of vehicles. Tail pipe emission reduction is one of the ways to achieve that but, it is a difficult process. This paper explores the alternative. This work describes a methodology for retrofitting the conventional drivetrain of a vehicle with an electric power unit. This work describes the development of a real world drive cycle for three wheeler Autorickshaws in Bengaluru city. For this, the micro trip generation method is employed, which captures the driving conditions encountered by the vehicle on a regular working day. A Bajaj RE 4 stroke CNG vehicle is used as the test vehicle throughout the process. A GPS based data logging system VBOX 3i is used for data acquisition. The vehicle dynamics are simulated to determine the power rating required for the electric motor to retrofit the IC engine using one dimensional longitudinal acceleration analysis. Coast down test results determine aerodynamic drag and rolling resistance coefficients. Dyno test helps us to understand the torque requirements for the electric motor to be retrofitted. The results of the mathematical model and the dyno test are then used to find a suitable electric motor. The adopted methodology in this work can be used to find the suitable power train replacement for any vehicle.