Simple CDI Circuit with SCR 2P4M

This series of CDI circuit is the same with one I have used on my CB motorcycle. At first I asked to uncle google and got a picture series of CDI circuit with R1 was 22K. After I applied on my motor, the ignition was not stable, sometimes even none at all. At first I suspected the pulser was not function properly, because I just put the pulser in the former site of platina. after I measure, the pulser's voltage is very small. Likely the sensor that generate the pulser's voltage didn't working properly. I have tried to tighten the sensor plate with a pulser, but the results remain unsatisfactory.

Then I switched to modify the CDI circuit. the point is the pulser's voltage was not able to trigger the scr. So I replaced R1 with smaller one. after trial and error, the right size for R1 is 10K. You can modify by your self for the right size of R1, depending on your pulser structure. But I think 10K is OK.

The 2nd component that I change is the ignition cappacitor. I used 3,25 microFarad TL cappacitor - cause hight and big ignition. You can widen the pulser's sensor in order to get bigger ignition. But you must be carefull, too much ignigtion means the SCR work too hard, and it can short. We can know it by the heat of SCR. Trial and error again he he.. :) Good luck.