Nugroho, Ali Ismunandar and , Ir. Amin Sulistyanto, S.T.M.T. (2026) Pengaruh Variasi Sudut Pengapian CDI Pada Mesin 4 Langkah 250 cc Terhadap Torsi, Daya, dan Konsumsi Bahan Bakar. Skripsi thesis, Universitas Muhammadiyah Surakarta.
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Abstract
Modifications to increase engine displacement (bore-up), accompanied by a rise in the compression ratio, necessitate adjustments to the ignition system to prevent detonation and optimize combustion efficiency. This study aims to analyze the effect of varying ignition timing angles on engine performance—specifically torque, power, and specific fuel consumption (SFC)—and to identify the optimal ignition timing configuration. The subject of this study is a 4-stroke Honda CB 125 SE motorcycle modified to 250 cc with a 12:1 compression ratio, using Pertamax RON 98 fuel. The experiment tested three ignition timing variations: factory standard (15° BTDC), advanced by 2° (17° BTDC), and retarded by 2° (13° BTDC) across an engine speed range of 6000–10,250 rpm. Torque and power were measured using a dynamometer, while SFC was determined using a graduated burette and a stopwatch. The results indicate that ignition timing variations significantly affect performance. The advanced ignition setting (17°) yielded the highest maximum torque of 24.84 Nm at 7,338 rpm and the best fuel economy with an SFC of 0.1941 kg/hp•h, although it produced the lowest peak power at 28.2 hp. Conversely, the standard ignition setting (15°) produced the highest peak power of 28.8 hp at 9,250 rpm with a torque of 23.78 Nm. The retarded ignition setting (13°) resulted in 24.09 Nm of torque and 28.4 hp of power but proved to be the least fuel-efficient configuration. It is concluded that the ignition curve advanced by 2° (17°) provides the best combination for optimizing torque and fuel efficiency, whereas the standard curve (15°) is recommended if the primary goal is achieving peak power at high RPM.
| Item Type: | Thesis (Skripsi) |
|---|---|
| Uncontrolled Keywords: | Ignition Timing, CDI, Honda CB 125 SE, Torque and Power, Fuel Consumption |
| Subjects: | T Technology > TJ Mechanical engineering and machinery T Technology > TL Motor vehicles. Aeronautics. Astronautics |
| Divisions: | Fakultas Teknik > S1 Teknik Mesin |
| Depositing User: | ALI ISMUNANDAR NUGROHO |
| Date Deposited: | 19 Aug 2026 01:36 |
| Last Modified: | 19 Aug 2026 01:36 |
| URI: | http://eprints.ums.ac.id/id/eprint/148421 |
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