| Progress in motorcycle industry has upturned very rapidly. For most people, performance of motorcycle considered unfavorable. Therefore, there are many modifications for motorcycle to get a better performance. Exhaust gas pipeline is one of many components that influence the performance of motorcycle. This last final assigment research is aim to find out the influence of exhaust gas pipeline diameter changes towards 4 steps gasoline motor performance. The exhaust gas pipeline which will be tested are 4 exhaust gas pipeline with using varying diameters. The tests that will be conducted involve testing in power and torque, testing spesific fuel consumption, testing actual fuel consumtion, and testing gas emissions. For the result of power and torque testing, it is found that the torque has increase to a maximum of 4,03% and also for the power which increase to a maximum of 4,31% by using a larger diameter exhaust gas pipeline. When using the exhaust gas pipeline which have larger diameter than standart one, obtained that fuel consumtion is relatively more wasteful because of power produced become greater. |