This paper deals with optimization and evaluation of a rubber ‘V’ belt operated continuously variable transmission (CVT) used with a 125 cc,four stroke engine, on a scooter.The paper consists of five parts. The first part describes the design and commissioning of a CVT Test Rig, where both the driving and driven pulleys are programmably controlled, giving details of its capabilities. The second part deals with Parameter Optimization of a CVT in order to obtain a good compromise between fuel economy and acceleration when used with a 125 cc, four stroke engine. Third part is devoted to determination of Transmission Efficiency of the CVT system and identification of those parameters which influence the efficiency. This aspect has not been dealt in previous publications. Experimental data on Temperature Measurements pertaining to the CVT under actual operating conditions in India, is presented in part four of the paper and this data is later used in the last part of the presentation which dwells on establishing a simulated test sequence to predict the Service Life of the Belt.