This study aims to develop a media of CDI ignition system trainer, which is feasible to apply the lessonsIgnition System Repairs and prove that the trainer CDI ignition system can improve the effectiveness oflearning in lessons Ignition System Repairs In State Vocational High School 1 Nganjuk.This research is the development of a model of development based on the four D models (Model 4D),which has been developed by Thiagarajan, Semmel and Semmel (Trianto, 2008:102). Researchdevelopment, there are 4 stages of Define, Design, Develop and Disseminate. Feasibility of media CDIignition system trainer depends on validation by 1 expert lecturer from the Department of MechanicalEngineering, State University of Surabaya and 2 expert teachers from the Motorcycle Technical SkillsProgram, State Vocational High School 1 Nganjuk. While the views of the effectiveness of learning fromstudent responses, observations and student learning outcomes, to study the response of students included10 students (limited trial) and 30 students (Disseminate test). The research instrument used was aquestionnaire validation by expert lecturer and expert teachers, student questionnaire responses,observations and tests of student learning outcomes. Data analysis was performed to determine thefeasibility and effectiveness of CDI Ignition System Trainer was developed.Based on research results, indicated that CDI ignition system trainer developed, worth to used as a mediaof learning in lessons Ignition System Repairs in the State Vocational High School 1 Nganjuk. It can beseen from the results of the validation performed by expert lecturer as much as 85,42% and 97,32% ofexpert teachers who are well worth category. On the results of research also proves that using CDIignition system trainer learning to be effective, due to (1) get a positive response from students that is equal to 87.00%), (2) increasing student activity from 36% (without using a trainer) to 49.33% (usingtrainer) or there is an increase of 13.33% student activities, (3) as well as to increase the percentage ofstudent from 60% (without using a trainer) to 100% (with using a trainer), or there is an increase of 40%.