EXPERIMENTAL STUDY ON THE EFFECT OF IGNITION ANGLE VARIATIONS AND FUEL OCTANE NUMBER ON THE PERFORMANCE OF 110CC UNDERBONE MOTORCYCLES

Abstract

Improving motorcycle performance is a primary focus in efforts to enhance energy efficiency. Motorcycle performance is strongly influenced by ignition timing and fuel octane rating, as the standard ignition timing of most motorcycles is designed for RON 88 fuel. This study aims to examine the effect of ignition timing variation using a programmable CDI and different fuel types on the performance of a 110 cc underbone motorcycle engine. The research variables include ignition timing and fuel types with different octane ratings (Pertalite RON 90, Pertamax RON 92 and Pertamax Turbo RON 98). An experimental method was employed by conducting tests on a chassis dynamometer to obtain power and torque data. The results show that adjusting the ignition timing using a programmable CDI and increasing the fuel octane rating significantly improve engine power and torque, particularly at medium and high engine speeds. The highest standard ignition timing—32° before top dead center using regular fuel—produced a maximum power of 7.8 HP at 7500–8000 RPM and a peak torque of 8.41 Nm at 4000 RPM. Meanwhile, with the programmable CDI, the highest power was achieved at an ignition timing of 34° before top dead center on map 2 using Pertamax Turbo (RON 98), generating a maximum power of 8 HP at 7500 RPM and a peak torque of 8.66 Nm at 4500 RPM.