Disc discs are the main component in a motorcycle braking system that functions to convert kinetic energy into heat energy through friction. The geometric design of the disc, including the diameter and number of holes, affects the effectiveness of braking as well as the heat dissipation ability. This study aims to analyze the effect of variations in diameter and number of holes on disc discs on braking distance and disc temperature. The research method used was an experimental method with three variations in disc diameter (190 mm, 220 mm, and 260 mm) and three variations in the number of holes (30, 36, and 42 holes). The test was carried out through a controlled braking procedure at an initial speed of 40 km/h on flat road surfaces with stable weather conditions. Braking distance data is measured using ultrasonic sensors, while disc temperature is recorded with a high-accuracy infrared thermometer. The results showed that the diameter of the disc disc had the most significant influence on the braking distance. The larger the diameter, the greater the braking moment resulting so that the stopping distance becomes shorter. The number of holes in the disc also plays a role in heat dissipation because the holes enlarge the heat dissipation area. However, the increase in the number of holes tends to slightly increase the braking distance due to a reduction in the area of frictional contact field. The most optimal configuration is found on a 260 mm diameter disc with 42 holes, which results in the shortest braking distance of 8.25 meters and the lowest temperature rise of 4.47°C.  Statistical analysis using Two-Way ANOVA confirmed that the diameter and number of holes had a significant effect individually, but there was no significant interaction between the two. These findings confirm that the selection of the right disc dimensions is critical to improving braking performance, thermal efficiency, and rider safety.

Automatic transmission motorcycles, especially those with 110cc engines, are increasingly in demand by the public because of their practicality. The performance of this motorcycle is greatly influenced by the transmission system, especially the Drive pulley and Roller components. The correct setting of the Drive pulley angle and Roller mass can improve engine performance and reduce noise, thus supporting driving comfort. This study aims to analyze the effect of variations in the Drive pulley angle and Roller mass on engine performance, in terms of power (HP), torque (Nm), and noise level (dB) at several engine speeds. The variations tested include the Drive pulley angle of 13.5°–14° and the Roller mass of 13–15 grams, with testing at 5000, 6000, 7000, and 8000 RPM. The test results show that the combination of the angle and Roller mass affects engine performance. At 5000 RPM, the combination of the 14° angle and 15 gram Roller produces the highest power, torque, and noise. At 6000 RPM, the combination of 13.8° and 13 grams produces a maximum power of 6.86 HP and 8.15 Nm of torque, with a noise of 97.40 dB. While at 7000–8000 RPM, the combination of 13.5° and 15 grams provides the best performance with 7.10 HP and 6.30 Nm of torque, accompanied by a noise of 104.17 dB. In general, increasing the angle and mass of the Roller increases performance, but is followed by an increase in noise.

Internal combustion engines generate thermal energy through the combustion of an air-fuel mixture. The incoming air must be filtered, as it contains impurities and particles. While air filters are commonly made from paper, they can also be developed using organic waste materials such as sugarcane bagasse and rice husk. This study aims to analyze the effect of biocomposite air filters on engine power, torque, and specific fuel consumption (SFC), by varying the material composition and the number of pleats, and comparing the results with those of a standard air filter. The method used is a quantitative experimental approach involving dyno testing on a 150 cc motorcycle engine. The tested material compositions include 50:50, 40:60, 30:70, 60:40, and 70:30 (sugarcane bagasse\:rice husk), with pleat counts of 28, 26, and 24. Results showed that the biocomposite filter with 28 pleats and a 30:70 composition delivered the best performance, producing 18.47 Hp and 16.66 Nm of torque—higher than the standard filter’s 17.98 Hp and 15.52 Nm. In terms of fuel efficiency, the 26-pleat filter with a 50:50 composition recorded the lowest SFC at 41.90 g/kWh, significantly better than the standard filter’s 53.03 g/kWh. Conversely, the 60:40 composition resulted in the highest SFC due to increased airflow resistance.