The expert system is a computer-based system that uses knowledge, facts, and reasoning techniques to solve problems that usually only experts in their field can solve. The development of an expert system is aimed to help Yamaha motorbike users to solve damage problems to a Yamaha Automatic motorcycle. Damage to a Yamaha Automatic motorcycle is a problem that requires experts (technicians) to rely on their knowledge to solve the problem. This system is built using the forward chaining method which is used to test the factors that have been entered by using the rules stored in the system until a conclusion is obtained. By using the forward chaining method, it is hoped that it can help the system in diagnosing the damage to the Yamaha Automatic motorcycle engine. Therefore, by applying an expert system for motorcycle engine damage, the problem of Yamaha Automatic motorcycle engine damage can be resolved.

The village of Tebat Benawa, the city of Pagar Alam, is located in a highland surrounded by many hills and trees. This is one of the factors that causes the signal emitted by the Base Tranceiver Station (BTS) tower which is ±12 km to the village of Tebat Benawa to be less good. Therefore, to improve the quality of the wifi network in the village of Tebat Benawa by utilizing the yagi grid extreme antenna as a signal amplifier. In this study, the Prepare, Plan, Design, Implemant, Operate, Optimaze (PPDIOO) method is used, because in this method there are steps that can assist in improving the quality of the wifi network by using an extreme yagi grid antenna in the village of Tebat Benawa. Prior to the installation of the Yagi Grid Extreme antenna, the wifi signal strength obtained was 2.1 Kbps, which means the signal strength is in the E or EDGE (Enchance Data Rate for GSM Eolution) signal range, which means that data transfer is slow. In measurements after using the Yagi Grid Extreme antenna, the signal strength in a closed room was obtained with a value of -32 dBm with a speed of 80 Mbps, but when the user's range was 20 meters from the antenna, the wifi signal strength became -89 dBm with a speed of 19 Mbps. While the test when the antenna is installed outside with a support pole, the wifi signal strength is -23 dBm and the speed is 72 Mbps, which means the signal is in the excellent or very good category.